The utility of health states after stroke: a systematic review of the literature.

BACKGROUND: To perform decision analyses that include stroke as one of the possible health states, the utilities of stroke states must be determined. We reviewed the literature to obtain estimates of the utility of stroke and explored the impact of the study population and the elicitation method. SUMMARY OF REVIEW: We searched various databases for articles reporting empirical assessment of utilities. Mean utilities of major stroke (Rankin Scale 4 to 5) and minor stroke (Rankin Scale 2 to 3) were calculated, stratified by study population and elicitation method. Additionally, the modified Rankin Scale was mapped onto the EuroQol classification system. Utilities were obtained from 23 articles. Patients at risk for stroke assigned utilities of 0.26 and 0.55 to major and minor stroke, respectively. Stroke survivors assigned higher utilities to both major (0.41) and minor stroke (0.72). The EuroQol completed by stroke survivors revealed a utility of 0.32 and 0.71 for major and minor stroke, respectively. Utilities elicited by the Standard Gamble were generally higher, while those obtained by the Visual Analogue Scale were lower than the Time Trade Off values. Remaining variation between utilities may be caused by differences in definitions of the health states. The mapped EuroQol indicated a utility of 0.64 for minor stroke and a value just below zero for major stroke. CONCLUSIONS: For minor stroke, a utility between 0.50 and 0.70 seems to be reasonable for both decision analyses and cost-effectiveness studies. The utility of major stroke may range between 0 and 0.30 and may possibly be negative.

Unstable preferences: a shift in valuation or an effect of the elicitation procedure?

OBJECTIVE: Many studies suggest that impaired health states are valued more positively when experienced than when hypothetical. This study investigated to what extent this discrepancy occurs and examined four possible explanations: non-corresponding description of the hypothetical health state, new understanding due to experience with the health state, valuation shift due to a new status quo, and instability of preference. PATIENTS AND METHODS: Fifty-five breast cancer patients evaluated their actually experienced health state, a radiotherapy scenario, and a chemotherapy control scenario before, during, and after postoperative radiotherapy. Utilities were elicited by means of a visual analog scale (VAS), a chained time tradeoff (TTO), and a chained standard gamble (SG). RESULTS: The discrepancy was found for all methods and was statistically significant for the TTO (predicted utilities: 0.89, actual utilities: 0.92, p < or = 0.05). During radiotherapy, significant differences (p < or = 0.01) were found between the utilities for the radiotherapy scenario and the actual health state by means of the VAS and the SG, suggesting non-corresponding description as an explanation. The utilities of the radiotherapy scenario and the chemotherapy control scenario remained stable over time, and thus new understanding, valuation shift, and instability could be ruled out as explanations. CONCLUSION: Utilities obtained through hypothetical scenarios may not be valid predictors of the value judgments of actually experienced health states. The discrepancy in this study seems to have been due to differences between the situations in question (non-corresponding descriptions).

Patients' utilities for cancer treatments: a study of the chained procedure for the standard gamble and time tradeoff.

OBJECTIVE: Temporary health states cannot be measured in the traditional way by means of techniques such as the time tradeoff (TTO) and the standard gamble (SG), where health states are chronic and are followed by death. Chained methods have been developed to solve this problem. This study assesses the feasibility of a chained TTO and a chained SG, and the consistency and concordance between the two methods. PATIENTS AND METHODS: Seventy female early-stage breast cancer patients were interviewed. In using both chained methods, the temporary health state to be evaluated was weighed indirectly with the aid of a temporary anchor health state. The patients were asked to evaluate their actual health states, a hypothetical radiotherapy scenario, and a hypothetical chemotherapy scenario. RESULTS: Sixty-eight patients completed the interview. The use of the anchor health state yielded some problems. A significant difference between the means of the TTO and the SG was found for the anchor health state only. For the other health states, the results were remarkably close, because the design avoided some of the bias effects in traditional measurements. CONCLUSION: The feasibility and the consistency of the chained procedure were satisfactory for both methods. The problems regarding the anchor health state can be solved by adapting the methods and by the use of a carefully chosen anchor health state. The chained method avoids biases present in the conventional method, and thereby the TTO and the SG may be reconciled. Moreover, there are several psychological advantages to the method, which makes it useful for diseases with uncertain prognoses.