Utilities Measured by Rating Scale, Time Trade-off, and Standard Gamble: Review and Reference for Health Care Professionals

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TL;DR

This systematic review of 164 articles (1966–1999) compiled 993 utility measurements for various health states, finding that time trade-off was the most common method (40%), followed by rating scale (31%) and standard gamble (29%). Utilities varied widely by disease, severity, and subject type, with rating scale consistently yielding the lowest values and standard gamble the highest. The compiled data serve as a benchmark for clinicians and researchers conducting decision analysis and cost-effectiveness analysis.

Full summary

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**Background:** Health-related quality of life (HRQOL) is a key outcome in clinical research and health policy. Utility is a single cardinal measure of HRQOL, ranging from 0 (death) to 1 (perfect health), and is essential for decision analysis and cost-effectiveness analysis. Three main methods—rating scale (RS), standard gamble (SG), and time trade-off (TTO)—are used to elicit utilities, but no comprehensive reference of published utility values existed. This systematic review aimed to compile and summarize utility data from the literature to serve as a resource for health care professionals.

**Methods:** The authors searched MEDLINE (1966–1999) using terms including "rating scal*," "time trade-off," "standard gamble," and "quality adjusted life years." From 29,044 retrieved abstracts, 376 full-text articles were reviewed, and 164 met inclusion criteria. Inclusion required utilities for a clearly stated health state or disease, elicited from patients or healthy volunteers, with values between 0 and 1. Exclusion criteria included utilities represented only by figures, multiattribute utility methods (e.g., EuroQol), or unclear reference points. Data were extracted on disease category, measurement method, subject type, and utility values (weighted mean, minimum, maximum).

**Key Results:** A total of 993 utility measurements were reported. TTO was used in 401 (40%) measurements, RS in 304 (31%), and SG in 288 (29%). The most frequently studied clinical categories were neurology, cardiology, nephrology, and gastroenterology/hepatology. Chronic health states dominated (907 measurements) over acute states (86). Specific conditions included coronary heart disease (52 utilities), physical disability from neurological diseases (45 utilities), chronic renal failure (74 utilities), and colorectal cancer (29 utilities). Mental or social dysfunction accounted for only 48 utilities (4.8%). Subjects were predominantly patients with the disease at issue (55%), followed by healthy volunteers (often medical staff or students) and patients with unrelated diseases. Utilities varied widely: for example, in coronary heart disease, mild cases ranged from 0.88 to 1.0, moderate from 0.832 to 0.997, and severe from 0.533 to 0.929. A consistent pattern emerged: RS yielded the lowest values, SG the highest. For instance, for moderate angina pectoris, RS gave 0.718, TTO 0.832, and SG 0.903 (Read et al.). For chronic renal failure on hemodialysis, utilities from patients ranged from 0.140 to 0.770 (RS), 0.490 to 0.551 (SG), and 0.390 to 0.810 (TTO). Healthy volunteers generally gave lower utilities than patients for the same condition.

**Clinical Implications:** This review provides a comprehensive reference of utility values for a wide range of health states, which can be used as benchmarks in decision analysis and cost-effectiveness analysis when individual patient utilities are unavailable. The finding that utilities differ by measurement method and subject type underscores the need for careful selection of elicitation technique and population. The predominance of chronic diseases and the underrepresentation of acute and mental health conditions highlight gaps for future research. The increasing number of utility studies (exponential growth in the 1990s) reflects the growing importance of patient preferences in evidence-based medicine and health policy.