PharmacoEconomics Open (2018) 2:203–208 https://doi.org/10.1007/s41669-017-0046-z ORIGINAL RESEARCH ARTICLE Health-Related Quality of Life in Patients Treated with Continuous Ambulatory Peritoneal Dialysis and Automated Peritoneal Dialysis in Singapore 1 2 3 4 5 4 • • • • • F. Yang N. Luo T. Lau Z. L. Yu M. W. Y. Foo K. Griva Published online: 14 July 2017 The Author(s) 2017. This article is an open access publication Abstract KDQOL symptoms than CAPD patients, suggesting that Objective This study aimed to compare the health-related APD was associated with better physical health and milder quality of life (HRQOL) in patients with end-stage renal dialysis-related symptoms. disease (ESRD) treated with continuous ambulatory peri- Conclusion The HRQOL of CAPD and APD patients was toneal dialysis (CAPD) and automated peritoneal dialysis largely equivalent in Singapore, but APD patients seemed (APD) in Singapore. to experience better physical health and be less bothered by Methods Thedatausedinthisstudy were from twocross- dialysis-related symptoms. sectional surveys of ESRD patients. HRQOL was assessed using the Kidney Disease Quality of Life (KDQOL) instru- ment. Socio-demographic characteristics and clinical data were Key Points for Decision Makers collected. The physical component summary (PCS) and mental component summary (MCS) scores, kidney disease component Peritoneal dialysis (PD) has been used as a practical summary (KDCS) score and its three scales (symptoms, effects, and widespread alternative to conventional burden), and one health utility score [EuroQol 5-dimension hemodialysis (HD) for end-stage renal disease (EQ-5D)] were calculated and compared between CAPD and (ESRD). APD using multivariate linear regression. There are two forms of PD, continuous ambulatory PD Results In total, 266 patients were included, with 145 on (CAPD) and automated PD (APD). It has been shown CAPD (mean age 60.8 years) and 121 on APD (mean age that the clinical outcomes for these two PD modalities 57.4 years). After adjustment for all variables collected, are comparable, so evidence on health-related quality APD patients had signiﬁcant higher scores in PCS and of life (HRQOL) is important in guiding nephrologists and patients in their choice of PD modality. & K. Griva The HRQOL of CAPD and APD patients was largely email@example.com equivalent in Singapore, but APD patients seemed to Manchester Centre for Health Economics, University of experience better physical health and be less Manchester, Manchester, UK bothered by dialysis-related symptoms. Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore Division of Nephrology, University Medicine Cluster, National University Health System, Singapore, Singapore 1 Introduction Department of Psychology, Faculty of Arts and Social Sciences, National University of Singapore, Singapore, Peritoneal dialysis (PD) has been used as a practical and Singapore 5 widespread alternative to conventional hemodialysis (HD) Department of Renal Medicine, Singapore General Hospital, for end-stage renal disease (ESRD) because of its Singapore, Singapore 204 F. Yang et al. advantages over HD, e.g., lower costs  and increased hemoglobin, dialysis vintage (i.e., time on dialysis), ﬂexibility in lifestyle . But it remains largely underuti- dependency status (i.e., self-care/assisted) and dialysis lized in most settings . adequacy (i.e., Kt/V) were retrieved from medical records. There are two forms of PD, continuous ambulatory PD Patients were included if they were aged C 21-year-old, (CAPD), which involves performing the PD exchanges on PD C 3 months, and able to communicate verbally and manually, and automated PD (APD), which refers to all provide informed consent. This study was approved by the forms of PD using a mechanical device to assist the Institutional Review Board of the National University delivery and drainage of dialysate. It has been shown that Health System, Singapore. the clinical outcomes for these two PD modalities are comparable [4, 5], so evidence on health-related quality of 2.2 Measures life (HRQOL) is important to contribute to guiding nephrologists and patients in their choice of PD modality. KDQOL-SF and KDQOL-36 are two commonly used In the provision of healthcare, HRQOL is commonly instruments developed speciﬁcally for individuals with evaluated, as it provides a good measure of treatment kidney disease and on dialysis . Both instruments have effectiveness by revealing how well an individual is been validated in ESRD patients in Singapore [18, 19]. functioning upon treatment . For ESRD patients, KDQOL-SF includes Short Form-36 (SF-36) and 43 kidney HRQOL is an important predictor of clinical outcomes, and disease-speciﬁc items; the KDQOL-36 contains a subset of poor HRQOL could independently predict death and hos- the KDQOL-SF items, with Short Form-12 (SF-12) and 24 pitalization of dialysis patients [7, 8]. As the majority of disease-speciﬁc items. Two summary scores, physical old and frail patients undergoing dialysis are unlikely to component summary (PCS) and mental component sum- receive kidney transplantation and would most likely mary (MCS), can be calculated from SF-12, and the disease- remain in dialysis until the end of life, the importance of speciﬁc part generates three kidney disease-speciﬁc scales, evaluating HRQOL is even more salient . However, i.e., symptoms, effects, and burden, and a kidney disease previous work of HRQOL outcomes for PD modalities has component summary (KDCS) score by averaging the three produced mixed evidence [10–12]. Furthermore, although disease-speciﬁc subscales . The EuroQol 5-dimension there has been an exponential increase in HRQOL research (EQ-5D) health utility score can be obtained from SF-12 in PD patients with Asian origin or in an Asian setting, using an established mapping function , and it has been most work has mainly compared PD with HD and has not demonstrated to be valid and sensitive in Singaporean dial- been across PD modalities [2, 13, 14]. ysis patients . For summary scores and health utility, Therefore, this study aimed to evaluate HRQOL higher scores represent better HRQOL, and for disease- between PD modalities and to explore factors which could speciﬁc scales, higher scores represent fewer/milder symp- affect their HRQOL. toms, effects or burden due to kidney disease and dialysis. 2.3 Statistical Analysis 2 Methods The socio-demographic and clinical characteristics were 2.1 Patients and Data compared ﬁrst, and then the three summary scores (PCS, MCS, and KDCS), three disease-speciﬁc scales and one Data used in this study were from two cross-sectional health utility score (EQ-5D) were compared between surveys, conducted between 2009  and 2013 . patients with CAPD and those with APD. In the subsequent Participants were recruited from the PD center of Singa- multivariate linear regression, all factor variables were pore General Hospital between 2009 and 2011 and from coded into categorical variables in case the association was the renal center of the National University Hospital not linear and then entered into seven models, one for each between 2012 and 2013. In both surveys, patients were of the HRQOL scores, regardless of their statistical sig- approached by trained interviewers while awaiting con- niﬁcance. All analyses were performed using STATA 14.0, sultation with a nephrologist. HRQOL data were collected with p \ 0.05 being considered signiﬁcant. using the kidney disease-speciﬁc HRQOL instrument Kidney Disease Quality of Life-Short Form (KDQOL-SF) in the ﬁrst survey and its abridged version, the 36-item 3 Results KDQOL (KDQOL-36), in the second survey, respectively. Socio-demographic characteristics were self-reported, and A total of 266 patients were included, with 145 on CAPD clinical data including co-morbidities measured using the and 121 on APD. Patients’ mean [standard deviation (SD)] Charlson Comorbidity Index (CCI), serum albumin and age was 59.3 (12.5) years, with 45.5% male, 74.4% HRQOL in Patients Treated with CAPD and APD in Singapore 205 Chinese, 80.8% having secondary or lower education, additional abdominal weight due to dwelling dialysate in 71.1% married, and 88.3% living in a public residence. The between the CAPD exchanges may be more likely to cause mean (SD) CCI was 5.08 (1.67), and mean (SD) serum discomfort and more interruptions to daily activities, hence albumin and hemoglobin levels were 30.3 (5.6) g/l and 10.9 impacting HRQOL. In contrast, APD being an overnight (1.69) g/dl, respectively. For dialysis parameters, the mean procedure entails no dialysate weight bearing and allows (SD) dialysis vintage was 3.55 (3.28) years, and the mean more ﬂexibility during the day for patients to pursue work, (SD) Kt/V value was 2.33 (0.88) per week. family and daily activities , which would be associated No signiﬁcant difference was observed in gender, eth- with better HRQOL. Also, compared to the manual nicity, marital status, housing type, co-morbidity, albumin exchanges in CAPD, the use of a dialysis machine in APD level, hemoglobin level, and dialysis adequacy between may lead to increased compliance with the prescribed PD CAPD and APD patients. But APD patients were younger regime and hence better disease management, which may than CAPD patients (mean age 57.4 vs. 60.8 years) and in turn contribute to higher physical HRQOL. On the other there were more individuals with high education, under- hand, we could not rule out the possibility that the study going assisted dialysis, and with shorter dialysis vintage in participants may have been self-selected for better out- the APD group. There was no signiﬁcant difference in the comes such as milder dialysis-related symptoms since our QOL scores, with the exception that APD patients had study cohort comprised prevalent PD patients with a mean higher KDQOL symptoms scores than CAPD patients dialysis vintage over 3 years. The health utility measured (76.0 vs. 69.8). Full characteristics and QOL scores are by the EQ-5D index showed a very small difference shown in Table 1. between CAPD and APD patients, suggesting that the In multivariate analyses, APD was signiﬁcantly associ- relative cost-effectiveness of these two PD modalities in ated with higher PCS and KDQOL symptoms scores, Singapore would be mainly determined by their survival indicating patients had better physical health and milder outcomes and associated costs. dialysis-related symptoms (Table 2). We also found the We also observed the impact of demographic, clinical following factors signiﬁcantly associated with higher and dialysis-related characteristics rather than PD modality HRQOL scores (Table 2): young or old age, high albumin itself on HRQOL. First, the impact of age on physical level, self-care dialysis and low dialysis adequacy. health was non-linear, with the middle-aged showing worse QOL, but old patients reporting comparable results to the young. A similar trend has been observed in previous 4 Discussion studies [2, 24]. This may be due to the greater adaptation to chronic dialysis and old patients’ lower expectations In view of the lack of clear evidence showing the advan- regarding their health. Second, high albumin level was tage of one PD modality in clinical outcomes, a compar- associated with higher scores in PCS, MCS, KDQOL ison of HRQOL between CAPD and APD patients would effects and health utility index. These associations make contribute to guiding the patient’s choice and provide good sense from the clinical perspective. A low albumin evidence for future cost-effectiveness assessment of PD may reﬂect malnutrition, and it is known to be strongly treatments. Few studies have investigated this topic, and related to higher risk for mortality and morbidity in dialysis results are conﬂicting. De Wit et al. observed better mental patients [2, 25]. Thus, it would be expected to be associated health in APD patients , while Bro et al. found no with poorer HRQOL. Third, self-care patients reported difference in both physical and mental health . better physical health and better health utility measured Regarding the kidney disease-speciﬁc QOL, one previous using EQ-5D, in line with the previous study . This study of incident PD patients showed that APD had result was not surprising because patients having physical advantages in KDQOL symptoms at 1 month, but signiﬁ- difﬁculties such as decreased vision and strength would be cance disappeared at 12 months . In our study, the more likely to use assisted PD; however, the impact of HRQOL of CAPD and APD were almost equivalent, but these physical difﬁculties cannot be adjusted by the anal- physical health and KDQOL symptoms were in favor of yses of this study. Last, higher dialysis adequacy was APD. associated with lower QOL scores, different from the The better physical health and fewer/milder symptoms previous study showing the positive correlation of Kt/V of APD patients may be mainly explained by the nature of and HRQOL . In clinical practice, a dialysis adequacy each PD modality. CAPD typically requires patients to target value is set to reduce the mortality risk , but to manually perform exchanges of dialysate ﬂuid four to ﬁve reach this target, patients might experience adverse effects times a day, whereas APD is usually applied at night when and the increased amount of time needed to perform the the patient is asleep using an automated machine. The great exchanges is less acceptable to patients . These factors time requirements of manual CAPD exchanges and might adversely affect QOL in PD patients. 206 F. Yang et al. Table 1 Socio-demographic, Total (n = 266) CAPD (n = 145) APD (n = 121) p value clinical, dialysis characteristics and the HRQOL scores of the Socio-demographic patients Age, mean (SD) 59.3 (12.5) 60.8 (11.4) 57.4 (13.6) 0.03* Young (45 years) 33 (12.4%) 15 (10.4%) 18 (14.9%) 0.13 Middle-aged (45–60 years) 90 (33.8%) 44 (30.3%) 46 (38.0%) Old ([60 years) 143 (53.8%) 86 (59.3%) 57 (47.1%) Gender 0.99 Male 121 (45.5%) 66 (45.5%) 55 (45.5%) Female 145 (54.5%) 79 (54.5%) 66 (54.5%) Ethnicity 0.76 Chinese 198 (74.4%) 109 (75.2%) 89 (73.6%) Malay/Indian/others 68 (25.6%) 36 (24.8%) 32 (26.4%) Educational level 0.02* Low (no/primary/secondary) 215 (80.8%) 125 (86.2%) 90 (74.4%) High (tertiary/above) 51 (19.2%) 20 (13.8%) 31 (25.6%) Marital status 0.99 Married 189 (71.1%) 103 (71.0%) 86 (71.1%) Other 77 (28.9%) 42 (29.0%) 35 (28.9%) Housing type 0.13 Private residence 31 (11.7%) 13 (9.0%) 18 (14.9%) Public residence 235 (88.3%) 132 (91.0%) 103 (85.1%) Clinical CCI 5.08 (1.67) 5.19 (1.48) 4.95 (1.87) 0.24 Albumin (g/l) 30.3 (5.6) 29.9 (5.2) 30.8 (6.0) 0.20 Hemoglobin (g/dl) 10.9 (1.69) 10.9 (1.67) 11.0 (1.71) 0.78 Dialysis Dependency status \0.01** Self-care 164 (61.6%) 102 (70.3%) 62 (51.2%) Assisted 102 (38.4%) 43 (29.7%) 59 (48.8%) Dialysis vintage (years) 3.55 (3.28) 4.50 (3.68) 2.42 (2.26) \0.001*** Dialysis adequacy Kt/V (per week) 2.33 (0.88) 2.28 (0.72) 2.40 (1.04) 0.26 QOL scores PCS 37.1 (9.8) 36.2 (9.6) 38.1 (9.7) 0.10 MCS 46.6 (11.1) 46.7 (11.2) 46.4 (11.1) 0.80 KDCS 58.7 (18.0) 57.6 (19.0) 60.0 (16.7) 0.29 Symptoms 72.6 (18.4) 69.8 (18.6) 76.0 (17.7) \0.01** Effects 69.1 (21.0) 67.9 (21.4) 70.5 (20.4) 0.31 Burden 34.4 (26.9) 35.2 (27.8) 33.5 (25.8) 0.62 EQ-5D 0.59 (0.21) 0.58 (0.21) 0.60 (0.22) 0.35 APD automated peritoneal dialysis, CAPD continuous ambulatory peritoneal dialysis, CCI Charlson Comorbidity Index, EQ-5D EuroQol 5-dimension, HRQOL health-related quality of life, KDCS kidney disease component summary, MCS mental component summary, PCS physical component summary, QOL quality of life, SD standard deviation * p \ 0.05, ** p \ 0.01, *** p \ 0.001 This study has several limitations. First, the HRQOL sectional data, and hence causal inferences cannot be data were from two different versions of the KDQOL, made. Third, the EQ-5D was based on mapping, which is which may inﬂuence patients’ responses due to context suboptimal compared to the direct use of a preference- effect . Second, analyses were based on cross- based measure. HRQOL in Patients Treated with CAPD and APD in Singapore 207 Table 2 Coefﬁcients of the independent predictor variables for HRQOL scores in peritoneal dialysis patients Independent variable Dependent variable Component summary score KDCS subscale Health utility PCS MCS KDCS Symptoms Effects Burden EQ-5D Young (45 years) Ref. Middle-aged (45–60 years) -5.31** 0.58 -2.44 -6.30 -2.46 1.44 -0.088 Old ([60 years) -2.81 2.69 4.58 0.95 6.97 5.83 -0.022 Male Ref. Female 0.61 -1.01 1.97 0.33 3.39 2.18 -0.003 Chinese Ref. Malay/Indians/others -2.56 0.77 -1.42 -0.81 -4.11 0.65 -0.039 Low education (no/primary/secondary) Ref. High education (tertiary/above) -1.10 2.31 -1.49 -2.36 -4.42 2.32 0.007 Non-married Ref. Married 1.23 -1.61 -2.90 -1.38 -3.81 -3.50 0.002 Housing type, public residence Ref. Housing type, private residence 0.80 0.08 2.13 2.89 -3.01 9.10 0.006 Low CCI (\5) Ref. High CCI (C5) -0.95 -1.32 -5.75 -2.28 -4.59 -10.4 -0.029 Low albumin level (\37 g/l) Ref. High albumin level (C37 g/l) 5.75** 4.90* 6.38 7.52 10.7* 0.90 0.146** Low hemoglobin level (\11 g/dl) Ref. High hemoglobin level (C11 g/dl) 1.70 0.62 2.47 2.33 1.97 3.12 0.037 CAPD Ref. APD 2.81* -0.56 2.63 6.90** 4.78 -3.78 0.039 Dependency status, assisted Ref. Dependency status, self-care 5.12*** -0.20 2.79 4.50 6.03 -2.16 0.085** Short dialysis vintage (\3.5 years) Ref. Long dialysis vintage (C3.5 years) 0.02 0.42 -0.97 -1.66 0.31 -1.55 0.011 Low dialysis adequacy (\2.0/week) Ref. High dialysis adequacy (C2.0/week) -1.63 -2.74 -1.69 -0.85 -2.53 -1.69 -0.065* Total R 0.17 0.05 0.06 0.09 0.08 0.04 0.15 All p values for a given independent variable are controlled for all other independent variables in the model APD automated peritoneal dialysis, CAPD continuous ambulatory peritoneal dialysis, CCI Charlson Comorbidity Index, EQ-5D EuroQol 5-dimension, HRQOL health-related quality of life, KDCS kidney disease component summary, MCS mental component summary, PCS physical component summary * p \ 0.05, ** p \ 0.01, *** p \ 0.001 Author Contributions FY designed the study, analyzed the data and 5 Conclusion drafted the article. KG and NL contributed to study design and the critical revision of the article draft. TL and MF provided medical The HRQOL of CAPD and APD patients was largely information. ZY helped with the original data collection. All authors equivalent in Singapore, but APD patients seemed to read and approved the ﬁnal manuscript. experience better physical health and be less bothered by Compliance with Ethical Standards dialysis-related symptoms. In the context of increasing advocacy for expanding PD utilization, more work is Funding No funding was received for this study. necessary to evaluate the outcomes of PD modalities to Conﬂict of interest Fan Yang, Nan Luo, Titus Lau, Zhenli Yu, inform modality selection and guide healthcare resource Marjorie Wai Yin Foo, and Konstadina Griva have no conﬂicts of allocation. interest. 208 F. Yang et al. Data availability statement The data that support the ﬁndings of this 13. Kim H, An JN, Kim DK, Kim MH, Kim YL, Park KS, Oh YK, study are available from the corresponding author upon reasonable Lim CS, Kim YS, Lee JP. Elderly peritoneal dialysis compared request. with elderly hemodialysis patients and younger peritoneal dial- ysis patients: competing risk analysis of a Korean Prospective cohort study. PLoS ONE. 2015;10(6):e0131393. Open Access This article is distributed under the terms of the 14. Chen JY, Wan EYF, Choi EPH, Chan AKC, Chan KHY, Tsang Creative Commons Attribution-NonCommercial 4.0 International JPY, Lam CLK. The health-related quality of life of Chinese License (http://creativecommons.org/licenses/by-nc/4.0/), which per- patients on hemodialysis and peritoneal dialysis. Patient. 2017;. mits any noncommercial use, distribution, and reproduction in any doi:10.1007/s40271-017-0256-6. medium, provided you give appropriate credit to the original 15. Griva K, Kang AW, Yu ZL, Mooppil NK, Foo M, Chan CM, author(s) and the source, provide a link to the Creative Commons Newman SP. 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