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Osteoarthritis: quality of life, comorbidities, medication and health service utilization assessed in a large sample of primary care patients

Osteoarthritis: quality of life, comorbidities, medication and health service utilization... Objective: To assess the gender related impact of osteoarthritis (OA) on quality of life (QoL) and health service utilization (HSU) of primary care patients in Germany. Methods: Cross sectional study with 1250 OA patients attending 75 primary care practices from March to May 2005. QoL was assessed using the GERMAN-AIMS2-SF. Data about comorbidities, prescriptions, health service utilization, and physical activity were obtained by questioning patients or from the patients' medical files. Depression was assessed by means of the Patient Health Questionnaire (PHQ-9). Results: 1021 (81.7%) questionnaires were returned. 347 (34%) patients were male. Impact of OA on QoL was different between gender: women achieved significantly higher scores in the AIMS 2- SF dimensions lower body (p < 0.01), symptom (p < 0.01), affect (p < 0.01) and work (p < 0.05). Main predictors of pain and disability were a high score in the "upper body "scale of the AIMS2-SF (beta = 0.280; p < 0.001), a high score in the PHQ-9 (beta = 0.214; p < 0.001), duration of OA (beta = 0.097; p = 0.004), age (beta = 0.090; p = 0.023) and the BMI (beta = 0.069; p = 0.034). Predictors of pain and disability did not differ between gender. 18.8 % of men and 19.7% of women had a concomitant depression. However, no gender differences occurred. Women visited their GP (mean 5.61 contacts in 6 months) more often than men (mean 4.08; p < 0.01); visits to orthopedics did not differ between gender. Conclusion: The extent to which OA impacts men and women differs in primary care patients. This might have resulted in the revealed differences in the pharmacological treatment and the HSU. Further research is needed to confirm our findings and to assess causality. the upcoming decades. Increasing life expectancy and Background Osteoarthritis is one of the most prevalent chronic dis- decreasing physical activity, leading to a constant increase eases worldwide and is associated with substantial impact in body weight, are regarded as underlying determinants on patients' individual quality of life as well as on health- of this development. Facing this situation, the WHO and care costs. Its prevalence is expected to rise significantly in the United Nations have declared the years 2000 to 2010 Page 1 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 to be the "Bone and Joint Decade" [1]. Since in the year sent. They were asked to return the questionnaires to the 2050 more than 50% of the population will be over 50 university by sending a stamped envelope and were years of age, the German health care system will be hit tre- informed that neither the GP nor the practice team had mendously by chronic illnesses like osteoarthritis [2]. any possibility to get knowledge of their answers. GPs cre- Most of these individuals will receive medical treatment ated a list of all addressed patients. Since the patients were in primary care settings, accounting for the growing addressed by their GP, detailed information about socio- number of studies dealing with OA in primary care [3-5]. demographic data, comorbidities, and medication were However, to date, relatively little is known about osteoar- also available for the non-respondents. thritis symptoms and their medical treatment in various subgroups of patients in primary care. Data collection Sociodemographic data included gender, age, educational Previous studies have focused on the prevalence and prog- level (1 = no school degree to 5 = university degree), work- nosis of OA [4,6]. Regarding prevalence, it is a frequently ing situation (1 = unemployed or retired, 2 = half time, 3 replicated result that women have a higher probability for = fulltime), and partnership (1 = living alone, 2 = mar- developing OA, especially OA of the knee [7,8]. Several ried/living with partner). As in the long version of the studies have suggested that not only prevalence but also AIMS2, some important comorbidities were assessed in the disease process is related to gender: women were the questionnaire: high blood pressure (HBP), diabetes, found to have more severe structural progression and a heart insufficiency (HI), coronary vessel disease (CVD), higher need to undergo surgical interventions than men elevated cholesterol level (low density lipoprotein (LDL) [6]. Other studies suggested that women with OA suffer > 200 mg/dl), ulcer or stomach disease, asthma/chronic from pain and disability to a greater extent compared to obstructive pulmonary disease (COPD), kidney disease, men and also that these dimensions of QoL are strongly cancer and stroke. Patient's answers were compared with associated with the social situation [9-11]. However, it comorbidities mentioned in the medical file via the list remains unclear how these findings can be explained. the GPs had created when addressing patients. This was done to increase validity of data and also to assess accu- The present study was performed to get a comprehensive racy of self reported diagnosis later on in the project. The overview of the health status and the healthcare received same procedure was performed for all other answers, by primary care patients with OA in Germany. We partic- including disease duration. For the analysis in this study ularly focused on differences related to gender because we the date form the medical files were used. Disease dura- hypothesized that men and women differ regarding tion was defined as the period form mentioning OA for health status and health service utilization (HSU). Fur- the first time in the medical file till now. Depressive disor- thermore, since it is known that quality of life (QoL) of der was diagnosed using the depression module of the OA patients is mainly determined by pain and disability German form of the Patient Health Questionnaire (PHQ- our aim was to assess factors that are associated with these 9) [15]. The PHQ-9 is a self-administered questionnaire two dimensions of QoL [8,12]. that enables to diagnose a Major or Minor Depression Epi- sode according to DSM-IV [16,17]. Moreover, the summa- rized scale score allows assessing the severity of Materials and methods The data used for this study are retrieved from the baseline depression. The PHQ-9 has proven to be a valid instru- assessment of the PraxArt project, which is financed by the ment for these assessments [18,19]. German Ministry for Education and Research over a period of 6 years, starting in 2003. The aim is to assess the The impact of OA on patients' health was assessed by the status of OA care and to search for possibilities to improve GERMAN-AIMS2-SF, which provides a comprehensive care as well as patients' quality of life by tailored interven- assessment of patients' health status comprising the tions. A randomly created sample of 75 general practition- dimensions physical limitation, symptom (reflecting per- ers in the area of Baden-Wuerttemberg and Bavaria has ceived pain), social (reflecting social contacts), affect been enrolled and recruited the patients for this survey. (reflecting mood), and work (reflecting the ability to work). It has recently been validated in German language Participants in a sample of OA patients [20]. As suggested in this study, To be eligible for inclusion, patients had to be adult and we divided the physical limitation scale of the AIMS2-SF diagnosed with osteoarthritis of the hip or knee according into upper body limitation and lower body limitation. To to the Committee of the American Rheumatism Associa- get a comprehensive view of the present situation of OA tion[13,14]. In each of the participating 75 practices, 15 patients, we collected all information about medication patients fulfilling these criteria were addressed consecu- and HSU from the patients' files. Since not all information tively. In total, 1250 questionnaires were administered to on medication (e.g. OTC medication), HSU (e.g. visits to patients after they had given their written informed con- healers) and treatments (e.g. acupuncture) were available Page 2 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 in the files, we assessed data about these parameters by were included in a stepwise regression analysis (method: straightforward questions. As described above, to com- enter) to reveal significant predictors. plete data, each questionnaire was compared with the medical file to which it was linked by an identification Results number on the participants list. So, data given by patients In total, 1311 patients were addressed by the GPs. 1250 of could be checked by comparing them with the medical them agreed to complete the questionnaire. 1021 of the file. Non-respondents were identified by comparing GPs 1250 (81.7%) patients returned the questionnaires, corre- lists of addressed patients with received questionnaires. sponding to at least 11 questionnaires in each practice. Regarding available data, including sociodemographic Patients were asked to mention all disease specific medi- variables, comorbidities and medication, no statistically cations they take additionally to prescriptions, including significant differences could be revealed between the non- OTC medication, homeopathic medication and sympto- respondents and the respondents. The main reason given matic slow-acting drugs in osteoarthritis (SYSADOA). for not participating was time effort. Among the enrolled SYSADOA is a generic term and covers a wide range of patients, 347 (34.0%) were male and 674 (66.0%) were substances. In Germany some of them have to be pre- female. If missing data occurred, they mainly occurred scribed, others are regarded as health food supplement, as within the same questionnaire, in total in 271 of the 1021 it is the case for instance in the United Kingdom. We questionnaires. In 123 cases the data could be completed assessed separately whether SYSADOAs were prescribed or from the patient file. whether patients bought them without prescription. Regarding Health Service Utilization (HSU), patients were 278 (80.1%) men were married or lived with a partner. asked about all contacts to orthopedic surgeons, healers, 376 (55.8%) women were engaged. This difference was received x-rays, physiotherapy, acupuncture and intraar- significant (p < 0.01). Completely retired from work were ticular injections. The International Physical Activity 233 (67.1%) men and 482 (71.5%) women. T-test for Questionnaire (IPAQ), a widespread assessment instru- group comparison revealed a significant difference in the ment was used to assess physical activity [21]. Inclusion of (formal) educational level between men (mean 2.61, SD patients did not start unless there was a written and unre- 1.1) and women (mean 2.38, SD 0.83). BMI, age, number stricted positive vote of the ethics committee of the Uni- of comorbidities or disease duration did not differ signif- versity of Heidelberg which was received in March 2005 icantly. Table 1 displays the characteristics of the study (approval number 021/2005). sample separated by localization of OA. Statistical analysis Quality of Life The data were analyzed with SPSS (version 12.0). Descrip- Regarding the impact of the disease on QoL, women tive analyses were performed for all variables. Continuous achieved significantly higher scores in the lower body variables are reported using means, standard deviations scale (2.98 vs. 2.39; p < 0.01), indicating more physical (SD), ranges and percentages. Unadjusted group compar- disability. Also the scores in the affect scale (3.10 vs. 2.60; isons were performed by means of Student's t-test. Nor- p < 0.01) and the symptom scale (5.12 vs. 4.49; p < 0.01) mality was tested by means of Kolmogorov-Smirnov-test indicated that women had significantly lower mood and to allow parametric test were applicable. For the compar- significantly more perceived pain than men (Table 1). ison of medication, comorbidities and depression catego- This result remained significant even if the ANCOVAs ries, which represented binary variables, the Chi-square- were adjusted for age, disease duration and comorbidities. test was used. Since the prevalence of depression differs Due to the inclusion criteria, focusing on patients with OA between men and women, the analysis was performed to the lower limb, the scores for the upper body limitation separately for gender[22]. Comparisons of depression were low, indicating no functional disability and did not prevalence (PHQ-scores), and HSU were made by ANCO- differ by gender. Differences in the work scale were nota- VAs adjusted for covariates that may have substantial ble (p < 0.05), but because of the large number of retired influence such as age, disease duration, comorbidities and patients the absolute numbers were small. QoL (AIMS2-SF scales assessing pain, physical limitation and social). Pain and disability are known to be the most Comorbidities important factors determining QoL in OA patients. To Table 2 displays the distribution of comorbidities sepa- assess predictors of these two factors, we calculated a sum rated by gender. As can be seen, high blood pressure and score of the AIMS "symptom" and "lower body" dimen- elevated cholesterol were the most common comorbid sion and calculated univariate correlations to sociodemo- conditions. Significant gender differences occurred only graphics and disease characteristics (by means of regarding HBP (p < 0.01). Asked about side effects related Spearman's rho). Factors with significant correlations to their osteoarthritis medication, 282 (81.27%) men and 563 (83.53) women agreed to have had side effects during Page 3 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 1: Characteristics of enrolled patients (n = 1021) separated by localization of OA total Hip Knee Men Women Men Women Number of participants 1021 191 236 156 438 Mean (SD) age (y) 66.1 (15.1) 64.3 (14.8) 65.3 (14.5) 66.5 (15.4) 67.1 (15.4) Disease duration (years) 13.7 (13.0) 11.7 (10.8) 12.3 (12.1) 14.1 (12.9) 15.2 (14.2) Body mass index (kg/m ) 28.3 (4.7) 27.4 (3.7) 27.1 (4.5) 28.6 (3.4) 29.2 (4.8) AIMS2-SF dimensions: Lower body ** 2.64 (2.04) 2.19 (1.97) 2.22 (2.25) 2.81 (2.71) 3.01 (2.95) Upper body 1.21 (2.02) 1.02 (1.86) 1.19 (1.17) 1.09 (1.77) 1.34 (2.32) Symptom ** 4.71 (2.42) 4.21 (2.13) 4.37 (2.19) 4.68 (2.83) 5.12 (2.91) Affect ** 2.77 (1.51) 2.39 (1.42) 2.81 (1.48) 2.52 (1.50) 3.01 (1.59) Social 4.57 (1.95) 4.26 (1.88) 4.44 (1.72) 4.45 (1.90) 4.82 (2.03) PHQ-9 sum score 15.7 (4.69) 14.9 (4.33) 15.9 (4.86) 15.4 (5.02) 16.1 (5.32) Unilateral OA (%) 150 (13.8) 32 (16.7) 41 (17.3) 32 (20.5) 45 (10.2) Number (%) with bilateral OA 871 (84.5) 159 (83.2) 195 (82.6) 124 (79.5) 393 (89.7) Number (%) with generalized OA 282 (25.4) 26 (13.6) 57 (24.1) 33 (21.1) 166 (37.8) Health Service Utilization the last 6 months. Interestingly, 77 men (22.19 %) and 146 women (21.66%) reported having ulcer or stomach Table 4 displays the health service utilization of the study pain in their history. sample within the last 6 months before the assessment. 86.4% of women and 76.7% of men visited their GP at Depression as comorbidity least once during the last half year. The amount of visits to In summary, 344 (99.1%) men and 668 (99.1%) women the GP varied widely from 0 to 12 during half a year with completely answered all 9 items of the PHQ-9 (table 3). a mean of 5.61 (SD 8.26) in women and 4.08 (SD 6.29) Among these, 38 (11.0%) men fulfilled criteria for a in men, representing a significant difference (p = 0.001) in major depressive episode and 27 (7.8 %) fulfilled criteria ANCOVAS adjusted for age, disease duration and comor- for a minor depressive episode. In women, 84 (12.6 %) bidities. Regarding visits to orthopedic surgeons, with a had a Major Depression episode and 47 (7.1 %) a Minor mean of 1.88, women had slightly more contacts than Depression episode. The overall prevalence of depressive men (mean 1.68), but the difference remained not statis- disorders was 19.4%. ANCOVA adjusted for age, disease tically significant after adjusting for covariates as men- duration and comorbidities revealed no significant differ- tioned above. More than a quarter of the patients received ences in PHQ-9 scores as well as in the occurrence of some acupuncture during the last half year and nearly a minor and major depression between men and women. quarter visited a traditional healer at least once. ANCO- Additionally, a Chi-square test was performed to compare VAs revealed that men received significantly more often the severity categories as binary data (no depression, injections in the joint (p = 0.026), but less acupuncture (p minor, major). This test also revealed no gender differ- = 0.042). Regarding physiotherapy, performed x-rays, and ence. visits to healers, no significant differences between gender could be revealed by means of ANCOVAs. Table 2: Comorbidities of the study sample (n = 1021) separated by gender gender High blood Elevated Diabetes Heart Coronary Ulcer/ Asthma/ Renal Cancer Stroke pressure** cholesterol Insufficiency vessel Gastritis COPD Insufficiency disease male 181 124 57 63 62 77 34 23 21 16 % 52.1 35.7 16.4 18.1 17.8 22.1 9.8 6.6 6.1 4.6 female 384 245 120 131 70 146 64 33 16 30 % 56.9 36.3 17.8 19.4 10.3 21.6 9.5 4.9 2.4 4.4 Total % 55.2 36.1 17.3 19.0 12.9 21.8 9.6 5.5 3.6 4.5 * p < 0.05; ** p < 0.01 in Chi-square test Page 4 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 3: Scores of the severity index of depression (PHQ-9 questionnaire) PHQ-9 scores Fulfilling criteria for Overall Gender N Mean SD Major Depression Minor Depression Depressive Disorder male 344 15.33 4.76 38 (11.0%) 27 (7.8 %) 65 (18.9%) female 668 15.95 4.63 84 (12.6 %) 47 (7.1 %) 131 (19.6%) ∑ 122 (12.0%) 74 (7.3%) 196 (19.4%) * p < 0.05; **p < 0.01; PHQ-9 scores compared by ANCOVA (adjusted for age, disease duration and comorbidities); severity categories by means of Chi-square-test Pharmacological treatment (beta = 0.280; p < 0.001), a high score in the PHQ-9 (beta NSAIDs represented the most frequently prescribed med- = 0.214; p < 0.001), duration of OA, age and the BMI. The ication in our study sample. Women received NSAIDs sig- whole model explained over 40% of variation in the nificantly more often (p = 0.043) than men, while the dependent variable. In a first approach the analyses was gender differences in the less often prescribed COX-2- made separately for both gender. Interestingly, predictors inhibitors were not significant (Table 5). Paracetamol was were the same for both gender, differences occurred only assessed because it is recommended as treatment of first with respect to the amount of the regression coefficient choice in most guidelines. Interestingly, Paracetamol was beta. Consequently, the results were displayed for both used only marginally. About 5% of patients of each gen- gender together. der were treated with opiates, women received signifi- cantly more opiates that belonged to step III according to Discussion the WHO step scheme of pain treatment. Overall, SYSA- Based on previous findings indicating biological differ- DOAs were only marginally prescribed, they were mostly ences (e.g. regarding the destruction of the cartilage) and taken as OTC medication. Regarding homeopathic medi- psychological differences (e.g. perception of pain) we cation, no significant difference could be observed hypothesized that men and women differ regarding many between gender. aspects of QoL and received care. This hypothesis could be confirmed: OA has higher impact on women in important Table 6 displays univariate correlations between the sum aspects of QoL such as pain, disability and mood. Similar score of the "symptom" and the "lower body" scale of the gender differences have been found e.g. by Woo et al. AIMS2-SF reflecting the main impact of arthritis on QoL, among Chinese people [23]. They received more NSAIDs pain and disability. Factors which achieved significance and visited their GP but not their specialist more fre- were entered into the regression model. As can be seen in quently than men and tended to have less intraarticular table 7, the main predictors of "pain and disability" are a injections. Interestingly, minor or major depressive epi- high score in the "upper body "scale of the AIMS2-SF sodes were not more frequent among women, even Table 4: Health service utilization of the study sample within 6 months During the last 6 months Gender At least one (%) Mean SD GP visits ** Male 76.7 4.08 6.29 Female 86.4 5.61 8.26 Visits to Orthopedic surgeon Male 56.8 1.68 3.17 Female 58.8 1.88 3.77 Physiotherapy* Male 51.3 5.66 11.52 Female 60.5 7.26 12.08 X-rays of joint Male 49.1 0.78 3.82 Female 52.5 0.98 4.15 Intraarticular injections** Male 34.3 1.20 4.38 Female 30.6 0.89 4.08 Acupuncture* Male 26.8 0.68 2.69 Female 27.9 1.22 4.53 Visits to Healers Male 22.5 0.21 1.31 Female 23.5 0.33 3.21 * p < 0.05, ** p < 0.01 in adjusted ANCOVA (age, disease duration, comorbidities) Page 5 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 5: Medication of the study sample (n = 1021) separated by gender Pain relievers Homeopathics SYSADOA SYSADOA Muscle (OTC)** (prescription) relaxant NSAID Opiats others Paracetamol Unselective COX-2 WHO II WHO III COX-inhibitors* Male (347) 120 (34.6%) 8 (2.3%) 18 (5.2%) 4 (%1.15)* 7 (2.0%) 2 (0.6%) 20 (2.0%) 34 (9.8%) 9 (2.6%) 8 (2.3%) Female (674) 276 (40.1%) 18 (2.7%) 32 (4.8%) 14 (2.0%)* 14 (2.0%)* 8 (1.2%)* 49 (2.5%) 78 (11.6%) 18 (2.7%) 14 (2.1%) ∑ 38.7% 2.6% 4.9% 1.8% 2.1% 1.0% 6.8% 10.7% 2.64 2.2 * p < 0.05; **p < 0.01 in Chi-square-test though the affect scale of the AIMS2-SF indicated lower gender differences occurred only regarding high blood mood among women. pressure [24-27]. Unfortunately, reliable data regarding comorbidities in OA patients are difficult to compare Regarding QoL, we found lower scores than Sany et al. did since different comorbid conditions have been assessed in a sample of rheumatoid patients regarding physical with different methods (e.g. self reports) in previous stud- limitation. However, we observed nearly the same mean ies. Groessl et al. who enrolled 363 OA patients in a pri- scores regarding the symptom scale. This finding may mary care setting in a health management organization indicate that patients suffering from OA are less limited in (HMO) in the United States reported on somewhat lower their mobility but appear to suffer from equivalent pain rates of HBP (28.8 %), which was the commonest comor- intensity than patients with rheumatoid arthritis (RA). bidity in their sample. Similar numbers were found by With regard to comorbidities which have an important Nilsdotter et al. [26]. Compared to national data, the impact on the QoL of patients suffering from osteoarthri- prevalence of HBP in Germany in this age group is expected to be over 55%, as was found in a large interna- tional comparison [28]. However, a limitation of our Table 6: Correlations between sociodemographic and disease findings is that no control group was available. characteristics with "pain and disability" Spearman's' rho p Regarding pain medication, Paracetamol, which is the first choice treatment according to most guidelines, was Sociodemographics only marginally prescribed. The main pillar in pharmaco- Age 0.052 0.129 logical treatment are NSAIDs such as Diclofenac [29-31]. Marital status -0.069 0.028 This is in accordance with the fact that NSAIDs are known Gender 0.096 0.002 to be increasingly used worldwide [32]. Interestingly, Education -0.076 0.016 IPAQ sum score -0.033 0.346 COX-2-inhibitors played no important role in prescrip- BMI 0.157 <0.001 tions. Our data also confirmed previous findings showing Health service utilization that the use of NSAIDs is more frequent among women GP contacts 0.251 <0.001 than men [33]. In the study of Linsell et al. 45.9% of OA Visits to Orthopedics 0.238 <0.001 patients stated to take pain killers frequently, which is Visits to healers 0.007 0.831 comparable to our results[3]. Amount of performed X-rays 0.254 <0.001 Physiotherapy 0.207 <0.001 Amount of prescriptions 0.178 <0.001 Regarding HSU, our data indicated a high HSU by OA Disease characteristics patients. However, it has to be noted that the German Duration of OA 0.269 <0.001 health care system is characterized by a high physician Amount of comorbidities 0.221 <0.001 contact-rate. The number of mean contacts per year and PHQ-9 sum score 0.475 <0.001 person in Germany, including all contacts to GPs and spe- Quality of life/AIMS2-Sf scales cialists, is 6.6 [34]. In Germany patients have free access to Upper body 0.398 0.001 secondary care, a referral is not required [35]. Thus, the Affect 0.472 0.001 Social 0.212 <0.001 revealed high amount of x-rays for example may also be Work -0.018 0.569 due to the unlimited accessibility of health care in Ger- many [36]. The reason why women visited their GP more often than men could be related to the higher pain scores tis as well as on the outcome of surgical interventions, of women, since it is known that pain is a strong predictor Page 6 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 7: Linear Regression analysis, dependent variable: "pain and disability" 2 2 R = 0.425; adjusted R = 0.402 F = 18,12; p < 0.001 Regression coeffizient beta T p Upper body* 0.280 7.978 <0.001 PHQ-9 sum score 0.214 4.817 <0.001 Duration of OA 0.097 2.923 0.004 Age 0.090 2.280 0.023 BMI 0.069 1.928 0.034 * AIMS2-SF scale for HSU among OA patients [27]. Interestingly, gender but the numbers of about 30% reported for RA patients differences could only be revealed regarding contacts to were not met [43]. GPs but not to specialists. An important weakness of the presented data is that, even though the analyses were Pain and disability have often been shown as the major adjusted for important covariates, HSU may have been burden of OA. Similar as in various other studies, women related to other reasons except arthritis, even though we achieved higher scores regarding both symptoms of OA asked patients to mention only contacts which were [23]. But interestingly, no gender differences could be related to OA. It should also be mentioned that we did not revealed regarding their predictors. control our data for patients' insurance. About 10% of patients are "privately" insured, resulting in higher reim- Despite the fact that our study has certain limitations and bursement for physicians. This may have influence on acknowledging the characteristics of the German health treatments, prescriptions as well as on referral rates. Our care system with e.g. a large number of non-surgical data regarding HSU reflect a finding that may be ignored orthopedics, the study gives a comprehensive overview. by many physicians: the important role of complemen- However, because of the wide range of aspects addressed tary alternative medicine (CAM) for patients with OA. As in this paper, it is not possible to describe the findings in Rao et al. could show the use of CAM is very common detail e.g. in the sense of revealing predictors for each var- among patients with RA. Our data regarding visits to heal- iable. The study represents the largest assessment of OA ers and received acupuncture are lower in comparison to patients in a primary care setting in Germany. the findings of Rao, who reported a frequent use of up to 90% among the RA patients, but at least more than a quar- Our findings regarding QoL and the burden of the disease ter of our patients reported on current use of CAM [37]. suggest that OA patients differ from patients suffering According to Rao, only half of the patients discuss the use from other forms of arthritis, especially RA. Our findings of CAM with their physician, so they should be aware of suggest that the impact of OA on men and women differs. this issue and address it in order to avoid treatment con- Even we could not prove causality we assume that this flicts or side effects. Interestingly, comparable findings may be have lead to the revealed differences in the phar- regarding CAM have been reported by Linsell et al. in a macological treatment and the use of the health care sys- sample of OA patients in the UK [3]. Many studies have tem. Further research is needed to confirm our results and assessed depression in patients with rheumatoid arthritis, assess causality. some of which indicate a higher risk among patients with RA than OA patients [38,39]. None of them enrolled as Competing interests much OA patients as we did. The importance of depres- The author(s) declare that they have no competing inter- sion for OA patients is related to the fact that it is an ests. important predictor for functional disability and an inde- pendent risk factor for mortality in RA [40]. Previous find- Authors' contributions ings regarding the prevalence among OA patients TR conceived and performed the study and drafted the indicated no increased prevalence [41,42]. Our data manuscript. GL performed the data management and sta- showed that 19.7% of women and 18.9% of men fulfilled tistical calculations. JS participated in the study design. All the criteria for a major or minor depressive episode. Data authors read and approved the final manuscript. regarding the point prevalence among the German popu- lation vary between 5–10 % in the general population Acknowledgements This study is part of the PRAXART project that aims to improve the quality [19]. In contrast to the general population, no gender dif- of life of patients suffering from OA. The project is financed by the German ferences could be revealed in our study sample. Our find- Ministry of Education and Research (BMBF), grant-number 01GK0301. We ings indicate a significant increase in the point prevalence would like to thank all participating patients and doctors. 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Page 8 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 43. Wittchen HU, Pittrow D: Prevalence, recognition and manage- ment of depression in primary care in Germany: the Depres- sion 2000 study. Hum Psychopharmacol 2002, 17 Suppl 1:S1-11. Publish with Bio Med Central and every scientist can read your work free of charge "BioMed Central will be the most significant development for disseminating the results of biomedical researc h in our lifetime." 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Osteoarthritis: quality of life, comorbidities, medication and health service utilization assessed in a large sample of primary care patients

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Springer Journals
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Copyright © 2007 by Rosemann et al; licensee BioMed Central Ltd.
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Medicine & Public Health; Orthopedics; Surgical Orthopedics
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1749-799X
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10.1186/1749-799X-2-12
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17603902
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Abstract

Objective: To assess the gender related impact of osteoarthritis (OA) on quality of life (QoL) and health service utilization (HSU) of primary care patients in Germany. Methods: Cross sectional study with 1250 OA patients attending 75 primary care practices from March to May 2005. QoL was assessed using the GERMAN-AIMS2-SF. Data about comorbidities, prescriptions, health service utilization, and physical activity were obtained by questioning patients or from the patients' medical files. Depression was assessed by means of the Patient Health Questionnaire (PHQ-9). Results: 1021 (81.7%) questionnaires were returned. 347 (34%) patients were male. Impact of OA on QoL was different between gender: women achieved significantly higher scores in the AIMS 2- SF dimensions lower body (p < 0.01), symptom (p < 0.01), affect (p < 0.01) and work (p < 0.05). Main predictors of pain and disability were a high score in the "upper body "scale of the AIMS2-SF (beta = 0.280; p < 0.001), a high score in the PHQ-9 (beta = 0.214; p < 0.001), duration of OA (beta = 0.097; p = 0.004), age (beta = 0.090; p = 0.023) and the BMI (beta = 0.069; p = 0.034). Predictors of pain and disability did not differ between gender. 18.8 % of men and 19.7% of women had a concomitant depression. However, no gender differences occurred. Women visited their GP (mean 5.61 contacts in 6 months) more often than men (mean 4.08; p < 0.01); visits to orthopedics did not differ between gender. Conclusion: The extent to which OA impacts men and women differs in primary care patients. This might have resulted in the revealed differences in the pharmacological treatment and the HSU. Further research is needed to confirm our findings and to assess causality. the upcoming decades. Increasing life expectancy and Background Osteoarthritis is one of the most prevalent chronic dis- decreasing physical activity, leading to a constant increase eases worldwide and is associated with substantial impact in body weight, are regarded as underlying determinants on patients' individual quality of life as well as on health- of this development. Facing this situation, the WHO and care costs. Its prevalence is expected to rise significantly in the United Nations have declared the years 2000 to 2010 Page 1 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 to be the "Bone and Joint Decade" [1]. Since in the year sent. They were asked to return the questionnaires to the 2050 more than 50% of the population will be over 50 university by sending a stamped envelope and were years of age, the German health care system will be hit tre- informed that neither the GP nor the practice team had mendously by chronic illnesses like osteoarthritis [2]. any possibility to get knowledge of their answers. GPs cre- Most of these individuals will receive medical treatment ated a list of all addressed patients. Since the patients were in primary care settings, accounting for the growing addressed by their GP, detailed information about socio- number of studies dealing with OA in primary care [3-5]. demographic data, comorbidities, and medication were However, to date, relatively little is known about osteoar- also available for the non-respondents. thritis symptoms and their medical treatment in various subgroups of patients in primary care. Data collection Sociodemographic data included gender, age, educational Previous studies have focused on the prevalence and prog- level (1 = no school degree to 5 = university degree), work- nosis of OA [4,6]. Regarding prevalence, it is a frequently ing situation (1 = unemployed or retired, 2 = half time, 3 replicated result that women have a higher probability for = fulltime), and partnership (1 = living alone, 2 = mar- developing OA, especially OA of the knee [7,8]. Several ried/living with partner). As in the long version of the studies have suggested that not only prevalence but also AIMS2, some important comorbidities were assessed in the disease process is related to gender: women were the questionnaire: high blood pressure (HBP), diabetes, found to have more severe structural progression and a heart insufficiency (HI), coronary vessel disease (CVD), higher need to undergo surgical interventions than men elevated cholesterol level (low density lipoprotein (LDL) [6]. Other studies suggested that women with OA suffer > 200 mg/dl), ulcer or stomach disease, asthma/chronic from pain and disability to a greater extent compared to obstructive pulmonary disease (COPD), kidney disease, men and also that these dimensions of QoL are strongly cancer and stroke. Patient's answers were compared with associated with the social situation [9-11]. However, it comorbidities mentioned in the medical file via the list remains unclear how these findings can be explained. the GPs had created when addressing patients. This was done to increase validity of data and also to assess accu- The present study was performed to get a comprehensive racy of self reported diagnosis later on in the project. The overview of the health status and the healthcare received same procedure was performed for all other answers, by primary care patients with OA in Germany. We partic- including disease duration. For the analysis in this study ularly focused on differences related to gender because we the date form the medical files were used. Disease dura- hypothesized that men and women differ regarding tion was defined as the period form mentioning OA for health status and health service utilization (HSU). Fur- the first time in the medical file till now. Depressive disor- thermore, since it is known that quality of life (QoL) of der was diagnosed using the depression module of the OA patients is mainly determined by pain and disability German form of the Patient Health Questionnaire (PHQ- our aim was to assess factors that are associated with these 9) [15]. The PHQ-9 is a self-administered questionnaire two dimensions of QoL [8,12]. that enables to diagnose a Major or Minor Depression Epi- sode according to DSM-IV [16,17]. Moreover, the summa- rized scale score allows assessing the severity of Materials and methods The data used for this study are retrieved from the baseline depression. The PHQ-9 has proven to be a valid instru- assessment of the PraxArt project, which is financed by the ment for these assessments [18,19]. German Ministry for Education and Research over a period of 6 years, starting in 2003. The aim is to assess the The impact of OA on patients' health was assessed by the status of OA care and to search for possibilities to improve GERMAN-AIMS2-SF, which provides a comprehensive care as well as patients' quality of life by tailored interven- assessment of patients' health status comprising the tions. A randomly created sample of 75 general practition- dimensions physical limitation, symptom (reflecting per- ers in the area of Baden-Wuerttemberg and Bavaria has ceived pain), social (reflecting social contacts), affect been enrolled and recruited the patients for this survey. (reflecting mood), and work (reflecting the ability to work). It has recently been validated in German language Participants in a sample of OA patients [20]. As suggested in this study, To be eligible for inclusion, patients had to be adult and we divided the physical limitation scale of the AIMS2-SF diagnosed with osteoarthritis of the hip or knee according into upper body limitation and lower body limitation. To to the Committee of the American Rheumatism Associa- get a comprehensive view of the present situation of OA tion[13,14]. In each of the participating 75 practices, 15 patients, we collected all information about medication patients fulfilling these criteria were addressed consecu- and HSU from the patients' files. Since not all information tively. In total, 1250 questionnaires were administered to on medication (e.g. OTC medication), HSU (e.g. visits to patients after they had given their written informed con- healers) and treatments (e.g. acupuncture) were available Page 2 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 in the files, we assessed data about these parameters by were included in a stepwise regression analysis (method: straightforward questions. As described above, to com- enter) to reveal significant predictors. plete data, each questionnaire was compared with the medical file to which it was linked by an identification Results number on the participants list. So, data given by patients In total, 1311 patients were addressed by the GPs. 1250 of could be checked by comparing them with the medical them agreed to complete the questionnaire. 1021 of the file. Non-respondents were identified by comparing GPs 1250 (81.7%) patients returned the questionnaires, corre- lists of addressed patients with received questionnaires. sponding to at least 11 questionnaires in each practice. Regarding available data, including sociodemographic Patients were asked to mention all disease specific medi- variables, comorbidities and medication, no statistically cations they take additionally to prescriptions, including significant differences could be revealed between the non- OTC medication, homeopathic medication and sympto- respondents and the respondents. The main reason given matic slow-acting drugs in osteoarthritis (SYSADOA). for not participating was time effort. Among the enrolled SYSADOA is a generic term and covers a wide range of patients, 347 (34.0%) were male and 674 (66.0%) were substances. In Germany some of them have to be pre- female. If missing data occurred, they mainly occurred scribed, others are regarded as health food supplement, as within the same questionnaire, in total in 271 of the 1021 it is the case for instance in the United Kingdom. We questionnaires. In 123 cases the data could be completed assessed separately whether SYSADOAs were prescribed or from the patient file. whether patients bought them without prescription. Regarding Health Service Utilization (HSU), patients were 278 (80.1%) men were married or lived with a partner. asked about all contacts to orthopedic surgeons, healers, 376 (55.8%) women were engaged. This difference was received x-rays, physiotherapy, acupuncture and intraar- significant (p < 0.01). Completely retired from work were ticular injections. The International Physical Activity 233 (67.1%) men and 482 (71.5%) women. T-test for Questionnaire (IPAQ), a widespread assessment instru- group comparison revealed a significant difference in the ment was used to assess physical activity [21]. Inclusion of (formal) educational level between men (mean 2.61, SD patients did not start unless there was a written and unre- 1.1) and women (mean 2.38, SD 0.83). BMI, age, number stricted positive vote of the ethics committee of the Uni- of comorbidities or disease duration did not differ signif- versity of Heidelberg which was received in March 2005 icantly. Table 1 displays the characteristics of the study (approval number 021/2005). sample separated by localization of OA. Statistical analysis Quality of Life The data were analyzed with SPSS (version 12.0). Descrip- Regarding the impact of the disease on QoL, women tive analyses were performed for all variables. Continuous achieved significantly higher scores in the lower body variables are reported using means, standard deviations scale (2.98 vs. 2.39; p < 0.01), indicating more physical (SD), ranges and percentages. Unadjusted group compar- disability. Also the scores in the affect scale (3.10 vs. 2.60; isons were performed by means of Student's t-test. Nor- p < 0.01) and the symptom scale (5.12 vs. 4.49; p < 0.01) mality was tested by means of Kolmogorov-Smirnov-test indicated that women had significantly lower mood and to allow parametric test were applicable. For the compar- significantly more perceived pain than men (Table 1). ison of medication, comorbidities and depression catego- This result remained significant even if the ANCOVAs ries, which represented binary variables, the Chi-square- were adjusted for age, disease duration and comorbidities. test was used. Since the prevalence of depression differs Due to the inclusion criteria, focusing on patients with OA between men and women, the analysis was performed to the lower limb, the scores for the upper body limitation separately for gender[22]. Comparisons of depression were low, indicating no functional disability and did not prevalence (PHQ-scores), and HSU were made by ANCO- differ by gender. Differences in the work scale were nota- VAs adjusted for covariates that may have substantial ble (p < 0.05), but because of the large number of retired influence such as age, disease duration, comorbidities and patients the absolute numbers were small. QoL (AIMS2-SF scales assessing pain, physical limitation and social). Pain and disability are known to be the most Comorbidities important factors determining QoL in OA patients. To Table 2 displays the distribution of comorbidities sepa- assess predictors of these two factors, we calculated a sum rated by gender. As can be seen, high blood pressure and score of the AIMS "symptom" and "lower body" dimen- elevated cholesterol were the most common comorbid sion and calculated univariate correlations to sociodemo- conditions. Significant gender differences occurred only graphics and disease characteristics (by means of regarding HBP (p < 0.01). Asked about side effects related Spearman's rho). Factors with significant correlations to their osteoarthritis medication, 282 (81.27%) men and 563 (83.53) women agreed to have had side effects during Page 3 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 1: Characteristics of enrolled patients (n = 1021) separated by localization of OA total Hip Knee Men Women Men Women Number of participants 1021 191 236 156 438 Mean (SD) age (y) 66.1 (15.1) 64.3 (14.8) 65.3 (14.5) 66.5 (15.4) 67.1 (15.4) Disease duration (years) 13.7 (13.0) 11.7 (10.8) 12.3 (12.1) 14.1 (12.9) 15.2 (14.2) Body mass index (kg/m ) 28.3 (4.7) 27.4 (3.7) 27.1 (4.5) 28.6 (3.4) 29.2 (4.8) AIMS2-SF dimensions: Lower body ** 2.64 (2.04) 2.19 (1.97) 2.22 (2.25) 2.81 (2.71) 3.01 (2.95) Upper body 1.21 (2.02) 1.02 (1.86) 1.19 (1.17) 1.09 (1.77) 1.34 (2.32) Symptom ** 4.71 (2.42) 4.21 (2.13) 4.37 (2.19) 4.68 (2.83) 5.12 (2.91) Affect ** 2.77 (1.51) 2.39 (1.42) 2.81 (1.48) 2.52 (1.50) 3.01 (1.59) Social 4.57 (1.95) 4.26 (1.88) 4.44 (1.72) 4.45 (1.90) 4.82 (2.03) PHQ-9 sum score 15.7 (4.69) 14.9 (4.33) 15.9 (4.86) 15.4 (5.02) 16.1 (5.32) Unilateral OA (%) 150 (13.8) 32 (16.7) 41 (17.3) 32 (20.5) 45 (10.2) Number (%) with bilateral OA 871 (84.5) 159 (83.2) 195 (82.6) 124 (79.5) 393 (89.7) Number (%) with generalized OA 282 (25.4) 26 (13.6) 57 (24.1) 33 (21.1) 166 (37.8) Health Service Utilization the last 6 months. Interestingly, 77 men (22.19 %) and 146 women (21.66%) reported having ulcer or stomach Table 4 displays the health service utilization of the study pain in their history. sample within the last 6 months before the assessment. 86.4% of women and 76.7% of men visited their GP at Depression as comorbidity least once during the last half year. The amount of visits to In summary, 344 (99.1%) men and 668 (99.1%) women the GP varied widely from 0 to 12 during half a year with completely answered all 9 items of the PHQ-9 (table 3). a mean of 5.61 (SD 8.26) in women and 4.08 (SD 6.29) Among these, 38 (11.0%) men fulfilled criteria for a in men, representing a significant difference (p = 0.001) in major depressive episode and 27 (7.8 %) fulfilled criteria ANCOVAS adjusted for age, disease duration and comor- for a minor depressive episode. In women, 84 (12.6 %) bidities. Regarding visits to orthopedic surgeons, with a had a Major Depression episode and 47 (7.1 %) a Minor mean of 1.88, women had slightly more contacts than Depression episode. The overall prevalence of depressive men (mean 1.68), but the difference remained not statis- disorders was 19.4%. ANCOVA adjusted for age, disease tically significant after adjusting for covariates as men- duration and comorbidities revealed no significant differ- tioned above. More than a quarter of the patients received ences in PHQ-9 scores as well as in the occurrence of some acupuncture during the last half year and nearly a minor and major depression between men and women. quarter visited a traditional healer at least once. ANCO- Additionally, a Chi-square test was performed to compare VAs revealed that men received significantly more often the severity categories as binary data (no depression, injections in the joint (p = 0.026), but less acupuncture (p minor, major). This test also revealed no gender differ- = 0.042). Regarding physiotherapy, performed x-rays, and ence. visits to healers, no significant differences between gender could be revealed by means of ANCOVAs. Table 2: Comorbidities of the study sample (n = 1021) separated by gender gender High blood Elevated Diabetes Heart Coronary Ulcer/ Asthma/ Renal Cancer Stroke pressure** cholesterol Insufficiency vessel Gastritis COPD Insufficiency disease male 181 124 57 63 62 77 34 23 21 16 % 52.1 35.7 16.4 18.1 17.8 22.1 9.8 6.6 6.1 4.6 female 384 245 120 131 70 146 64 33 16 30 % 56.9 36.3 17.8 19.4 10.3 21.6 9.5 4.9 2.4 4.4 Total % 55.2 36.1 17.3 19.0 12.9 21.8 9.6 5.5 3.6 4.5 * p < 0.05; ** p < 0.01 in Chi-square test Page 4 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 3: Scores of the severity index of depression (PHQ-9 questionnaire) PHQ-9 scores Fulfilling criteria for Overall Gender N Mean SD Major Depression Minor Depression Depressive Disorder male 344 15.33 4.76 38 (11.0%) 27 (7.8 %) 65 (18.9%) female 668 15.95 4.63 84 (12.6 %) 47 (7.1 %) 131 (19.6%) ∑ 122 (12.0%) 74 (7.3%) 196 (19.4%) * p < 0.05; **p < 0.01; PHQ-9 scores compared by ANCOVA (adjusted for age, disease duration and comorbidities); severity categories by means of Chi-square-test Pharmacological treatment (beta = 0.280; p < 0.001), a high score in the PHQ-9 (beta NSAIDs represented the most frequently prescribed med- = 0.214; p < 0.001), duration of OA, age and the BMI. The ication in our study sample. Women received NSAIDs sig- whole model explained over 40% of variation in the nificantly more often (p = 0.043) than men, while the dependent variable. In a first approach the analyses was gender differences in the less often prescribed COX-2- made separately for both gender. Interestingly, predictors inhibitors were not significant (Table 5). Paracetamol was were the same for both gender, differences occurred only assessed because it is recommended as treatment of first with respect to the amount of the regression coefficient choice in most guidelines. Interestingly, Paracetamol was beta. Consequently, the results were displayed for both used only marginally. About 5% of patients of each gen- gender together. der were treated with opiates, women received signifi- cantly more opiates that belonged to step III according to Discussion the WHO step scheme of pain treatment. Overall, SYSA- Based on previous findings indicating biological differ- DOAs were only marginally prescribed, they were mostly ences (e.g. regarding the destruction of the cartilage) and taken as OTC medication. Regarding homeopathic medi- psychological differences (e.g. perception of pain) we cation, no significant difference could be observed hypothesized that men and women differ regarding many between gender. aspects of QoL and received care. This hypothesis could be confirmed: OA has higher impact on women in important Table 6 displays univariate correlations between the sum aspects of QoL such as pain, disability and mood. Similar score of the "symptom" and the "lower body" scale of the gender differences have been found e.g. by Woo et al. AIMS2-SF reflecting the main impact of arthritis on QoL, among Chinese people [23]. They received more NSAIDs pain and disability. Factors which achieved significance and visited their GP but not their specialist more fre- were entered into the regression model. As can be seen in quently than men and tended to have less intraarticular table 7, the main predictors of "pain and disability" are a injections. Interestingly, minor or major depressive epi- high score in the "upper body "scale of the AIMS2-SF sodes were not more frequent among women, even Table 4: Health service utilization of the study sample within 6 months During the last 6 months Gender At least one (%) Mean SD GP visits ** Male 76.7 4.08 6.29 Female 86.4 5.61 8.26 Visits to Orthopedic surgeon Male 56.8 1.68 3.17 Female 58.8 1.88 3.77 Physiotherapy* Male 51.3 5.66 11.52 Female 60.5 7.26 12.08 X-rays of joint Male 49.1 0.78 3.82 Female 52.5 0.98 4.15 Intraarticular injections** Male 34.3 1.20 4.38 Female 30.6 0.89 4.08 Acupuncture* Male 26.8 0.68 2.69 Female 27.9 1.22 4.53 Visits to Healers Male 22.5 0.21 1.31 Female 23.5 0.33 3.21 * p < 0.05, ** p < 0.01 in adjusted ANCOVA (age, disease duration, comorbidities) Page 5 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 5: Medication of the study sample (n = 1021) separated by gender Pain relievers Homeopathics SYSADOA SYSADOA Muscle (OTC)** (prescription) relaxant NSAID Opiats others Paracetamol Unselective COX-2 WHO II WHO III COX-inhibitors* Male (347) 120 (34.6%) 8 (2.3%) 18 (5.2%) 4 (%1.15)* 7 (2.0%) 2 (0.6%) 20 (2.0%) 34 (9.8%) 9 (2.6%) 8 (2.3%) Female (674) 276 (40.1%) 18 (2.7%) 32 (4.8%) 14 (2.0%)* 14 (2.0%)* 8 (1.2%)* 49 (2.5%) 78 (11.6%) 18 (2.7%) 14 (2.1%) ∑ 38.7% 2.6% 4.9% 1.8% 2.1% 1.0% 6.8% 10.7% 2.64 2.2 * p < 0.05; **p < 0.01 in Chi-square-test though the affect scale of the AIMS2-SF indicated lower gender differences occurred only regarding high blood mood among women. pressure [24-27]. Unfortunately, reliable data regarding comorbidities in OA patients are difficult to compare Regarding QoL, we found lower scores than Sany et al. did since different comorbid conditions have been assessed in a sample of rheumatoid patients regarding physical with different methods (e.g. self reports) in previous stud- limitation. However, we observed nearly the same mean ies. Groessl et al. who enrolled 363 OA patients in a pri- scores regarding the symptom scale. This finding may mary care setting in a health management organization indicate that patients suffering from OA are less limited in (HMO) in the United States reported on somewhat lower their mobility but appear to suffer from equivalent pain rates of HBP (28.8 %), which was the commonest comor- intensity than patients with rheumatoid arthritis (RA). bidity in their sample. Similar numbers were found by With regard to comorbidities which have an important Nilsdotter et al. [26]. Compared to national data, the impact on the QoL of patients suffering from osteoarthri- prevalence of HBP in Germany in this age group is expected to be over 55%, as was found in a large interna- tional comparison [28]. However, a limitation of our Table 6: Correlations between sociodemographic and disease findings is that no control group was available. characteristics with "pain and disability" Spearman's' rho p Regarding pain medication, Paracetamol, which is the first choice treatment according to most guidelines, was Sociodemographics only marginally prescribed. The main pillar in pharmaco- Age 0.052 0.129 logical treatment are NSAIDs such as Diclofenac [29-31]. Marital status -0.069 0.028 This is in accordance with the fact that NSAIDs are known Gender 0.096 0.002 to be increasingly used worldwide [32]. Interestingly, Education -0.076 0.016 IPAQ sum score -0.033 0.346 COX-2-inhibitors played no important role in prescrip- BMI 0.157 <0.001 tions. Our data also confirmed previous findings showing Health service utilization that the use of NSAIDs is more frequent among women GP contacts 0.251 <0.001 than men [33]. In the study of Linsell et al. 45.9% of OA Visits to Orthopedics 0.238 <0.001 patients stated to take pain killers frequently, which is Visits to healers 0.007 0.831 comparable to our results[3]. Amount of performed X-rays 0.254 <0.001 Physiotherapy 0.207 <0.001 Amount of prescriptions 0.178 <0.001 Regarding HSU, our data indicated a high HSU by OA Disease characteristics patients. However, it has to be noted that the German Duration of OA 0.269 <0.001 health care system is characterized by a high physician Amount of comorbidities 0.221 <0.001 contact-rate. The number of mean contacts per year and PHQ-9 sum score 0.475 <0.001 person in Germany, including all contacts to GPs and spe- Quality of life/AIMS2-Sf scales cialists, is 6.6 [34]. In Germany patients have free access to Upper body 0.398 0.001 secondary care, a referral is not required [35]. Thus, the Affect 0.472 0.001 Social 0.212 <0.001 revealed high amount of x-rays for example may also be Work -0.018 0.569 due to the unlimited accessibility of health care in Ger- many [36]. The reason why women visited their GP more often than men could be related to the higher pain scores tis as well as on the outcome of surgical interventions, of women, since it is known that pain is a strong predictor Page 6 of 9 (page number not for citation purposes) Journal of Orthopaedic Surgery and Research 2007, 2:12 http://www.josr-online.com/content/2/1/12 Table 7: Linear Regression analysis, dependent variable: "pain and disability" 2 2 R = 0.425; adjusted R = 0.402 F = 18,12; p < 0.001 Regression coeffizient beta T p Upper body* 0.280 7.978 <0.001 PHQ-9 sum score 0.214 4.817 <0.001 Duration of OA 0.097 2.923 0.004 Age 0.090 2.280 0.023 BMI 0.069 1.928 0.034 * AIMS2-SF scale for HSU among OA patients [27]. Interestingly, gender but the numbers of about 30% reported for RA patients differences could only be revealed regarding contacts to were not met [43]. GPs but not to specialists. An important weakness of the presented data is that, even though the analyses were Pain and disability have often been shown as the major adjusted for important covariates, HSU may have been burden of OA. Similar as in various other studies, women related to other reasons except arthritis, even though we achieved higher scores regarding both symptoms of OA asked patients to mention only contacts which were [23]. But interestingly, no gender differences could be related to OA. It should also be mentioned that we did not revealed regarding their predictors. control our data for patients' insurance. About 10% of patients are "privately" insured, resulting in higher reim- Despite the fact that our study has certain limitations and bursement for physicians. This may have influence on acknowledging the characteristics of the German health treatments, prescriptions as well as on referral rates. Our care system with e.g. a large number of non-surgical data regarding HSU reflect a finding that may be ignored orthopedics, the study gives a comprehensive overview. by many physicians: the important role of complemen- However, because of the wide range of aspects addressed tary alternative medicine (CAM) for patients with OA. As in this paper, it is not possible to describe the findings in Rao et al. could show the use of CAM is very common detail e.g. in the sense of revealing predictors for each var- among patients with RA. Our data regarding visits to heal- iable. The study represents the largest assessment of OA ers and received acupuncture are lower in comparison to patients in a primary care setting in Germany. the findings of Rao, who reported a frequent use of up to 90% among the RA patients, but at least more than a quar- Our findings regarding QoL and the burden of the disease ter of our patients reported on current use of CAM [37]. suggest that OA patients differ from patients suffering According to Rao, only half of the patients discuss the use from other forms of arthritis, especially RA. Our findings of CAM with their physician, so they should be aware of suggest that the impact of OA on men and women differs. this issue and address it in order to avoid treatment con- Even we could not prove causality we assume that this flicts or side effects. Interestingly, comparable findings may be have lead to the revealed differences in the phar- regarding CAM have been reported by Linsell et al. in a macological treatment and the use of the health care sys- sample of OA patients in the UK [3]. Many studies have tem. Further research is needed to confirm our results and assessed depression in patients with rheumatoid arthritis, assess causality. some of which indicate a higher risk among patients with RA than OA patients [38,39]. None of them enrolled as Competing interests much OA patients as we did. The importance of depres- The author(s) declare that they have no competing inter- sion for OA patients is related to the fact that it is an ests. important predictor for functional disability and an inde- pendent risk factor for mortality in RA [40]. Previous find- Authors' contributions ings regarding the prevalence among OA patients TR conceived and performed the study and drafted the indicated no increased prevalence [41,42]. Our data manuscript. GL performed the data management and sta- showed that 19.7% of women and 18.9% of men fulfilled tistical calculations. JS participated in the study design. All the criteria for a major or minor depressive episode. Data authors read and approved the final manuscript. regarding the point prevalence among the German popu- lation vary between 5–10 % in the general population Acknowledgements This study is part of the PRAXART project that aims to improve the quality [19]. In contrast to the general population, no gender dif- of life of patients suffering from OA. The project is financed by the German ferences could be revealed in our study sample. Our find- Ministry of Education and Research (BMBF), grant-number 01GK0301. We ings indicate a significant increase in the point prevalence would like to thank all participating patients and doctors. 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Journal of Orthopaedic Surgery and Research – Springer Journals

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