An Economic Analysis of Strategies for the Use of Contrast Media for Diagnostic Cardiac CatheterizationBarrett, Brendan J.; Parfrey, Patrick S.; Foley, Robert N.; Detsky, Allan S.
doi: 10.1177/0272989X9401400403pmid: 7808208
A decision tree model was used to estimate the incremental cost per quality-adjusted life year (QALY) of low- as opposed to high-osmolality contrast media for cardiac angiography. Analyses were done from the viewpoints of a third-party payer and society using data from a randomized trial and the literature. Assuming low-osmolality media reduce the risk of myocardial infarction and stroke, the incremental cost per QALY gained with these media is $17,264 in high-risk or $47,874 in low-risk patients for a third-party payer. From a societal viewpoint, the corresponding costs are $649 and $35,509. These estimates are sensitive to the cost and volume of the contrast medium employed and to the estimate of reduction in severe adverse events with low-osmolality media. The authors conclude that, in the context of restricted budgets, limiting the use of low-osmolality media to high-risk patients is justifiable, as the incremental cost per QALY in high-risk patients may be reasonable and it is not certain that low-osmolality media prevent severe or fatal events. A considerable reduction in the cost per QALY gained is possible by minimizing the volume of contrast medium used. Key words: contrast media; low-osmolality; high-osmolality; cardiac angiography; cost-utility; cost-benefit; cost-effectiveness; economic analysis. (Med Decis Making 1994;14:325- 335)
Developing and Testing a Multimedia Presentation of a Health-state DescriptionGoldstein, Mary Kane; Clarke, Ann E.; Michelson, David; Garber, Alan M.; Bergen, Merlynn R.; Lenert, Leslie A.
doi: 10.1177/0272989X9401400404pmid: 7528868
Quality-adjustment weights for health states are an essential component of cost-utility anal ysis (CUA). Quality-adjustment weights are obtained by presenting large numbers of subjects with multiattribute descriptions of health states for rating. Comprehending multiattribute health states is a difficult task for most respondents. The authors hypothesized that multimedia (MM) presentation using computers might facilitate this task better than would a paper-based text (Text). To test this hypothesis, they developed closely matched MM and Text descriptions of health states in the first-person narrative style, and developed a method of testing the presentation of a health state. Subjects were randomized to exposure to either MM or Text and subject recall of the health state and recognition of features of the health state were tested. How well defined the preferences of the subjects were after each presentation method was assessed by having the subjects mark on a double-anchored visual-analog scale the "best" and "worst" they believed the quality of life in the health state might be. MM subjects had better recall (11.85 vs 9.44 of a total of 24 meaning units, p = 0.098) and better recognition (4.71 vs 4.22, p = 0.08). The average interval between the "best" and "worst" ratings was shorter for the MM subjects (2.19 cm vs 3.26 cm, p = 0.12). The results suggest that: 1) MM presentation results in better recall and recognition, indicating better transfer of information; 2) MM presentation appears to result in better definition of preferences (a smaller preference interval), suggesting better integration of information into subject preference; and 3) recall and recognition testing of a health-state description can identify material in the description that has an unintended impact on the respondents. Key words: cost-utility analysis; communication medium; quality-adjustment weights; multimedia; health-state de scription. (Med Decis Making 1994;14:336-344)
Designing a Simpler High Blood Cholesterol Case Detection StrategyHofer, Timothy; Weissfeld, Joel
doi: 10.1177/0272989X9401400406pmid: 7808210
Objective: To determine whether the complex strategy of lipid measurements for the detection of patients with high blood cholesterol levels proposed by the first Expert Panel of the National Cholesterol Education Panel (NCEP) could be simplified without significant loss of accuracy. Design: Decision-analysis-based model of competing case detection strategies as com pared with the NCEP strategy. A Markov model was used to estimate numbers of people treated over ten years as a result of the different classification strategies. Data sources: Conditional probabilities for the decision trees were derived from cholesterol distributions in national population-based surveys. Parameters for the Markov model were from published major epidemiologic studies and clinical trials. Main outcome measures: Misclassification to treatment vs non-treatment as a continuous function of the distribution of true low-density lipoprotein (LDL). Results : A simplified strategy was designed that screens high-risk persons with two LDL measurements and low-risk people with one cholesterol measurement followed by two LDL measurements if the initial value is high. This algorithm requires 37% fewer measurements to classify a population. The overall accuracy of classification to treatment based on the NCEP I cutoff points is high, with a positive predictive value of 95% and a negative predictive value of 87% (relative to 97% and 80%, respectively, for the NCEP I protocol). This strategy is very similar to published NCEP II guidelines. A strategy that recommends an LDL determination for everyone, as a recent NIH consensus panel sug gested, also significantly reduces the number of measurements required by 48%. The positive predictive value is 93%, vs 97% for the NCEP I protocol. The negative predictive value is 92%, vs 80% for the NCEP I. Conclusions: The complex measurement strategy initially proposed in the NCEP I guidelines did not improve accuracy of classification over the simpler and more convenient strategies that the authors evaluated and that have been substantially adopted in the NCEP II guidelines. Key words: mathematical models; laboratory measure ment; hyperlipidemia; cost-effectiveness analysis; lipids. (Med Decis Making 1994;14:357- 368)
Comparison of the Rating Scale and the Standard Gamble in Measuring Patient Preferences for Outcomes of Gallstone DiseaseBass, Eric B.; Steinberg, Earl P.; Pitt, Henry A.; Griffiths, Robert I.; Lillemoe, Keith D.; Saba, George P.; Johns, Christina
doi: 10.1177/0272989X9401400401pmid: 7808206
To estimate patient preferences for gallstone-related treatments and outcomes, and assess how preferences vary by patient characteristics and scaling technique, the authors randomly assigned 40 patients without gallstones to interviews based on a rating scale (n = 22) and a standard gamble (n = 18). The patients assigned preference values (possible values 0 to 1) to open cholecystectomy (mean 0.45 by rating scale, 0.78 by standard gamble), laparoscopic cholecystectomy (0.71, 0.91), extracorporeal shock-wave lithotripsy (0.77, 0.89), acute cholecystitis (0.36, 0.77), lifetime biliary colic (0.41, 0.71), postcholecystectomy syn drome (0.43, 0.79), asymptomatic stone necessitating treatment with bile acids (0.76, 0.96), and surgical scar (0.79, 0.998). Preferences varied little by age, gender, or race. Standard gamble values were highly correlated with, but significantly greater than, rating scale values. The authors conclude that patients' preferences for gallstone-related conditions generally are significantly less than one, and differ markedly by the scaling technique used to derive them. These results should be considered when patient preferences are incorporated into analyses of gallstone treatments. Key words: patient preference values; rating scale; stan dard gamble; gallstones; cholecystectomy; lithotripsy. (Med Decis Making 1994;14:307- 314)