OBJECTIVES

We aim to systematically review of all original articles assessing direct utilities in depression using time-trade off (TTO) method.

METHODS

A systematic literature review was conducted in November 2020 in four online databases (PubMed, Web of Science, Psychinfo and Cochrane Library). Search strategy was built up as combination of different spellings of TTO terms and “depression” keyword. Inclusion criteria were (1) original publications (2) eliciting TTO utility for depression.

RESULTS

Of the 264 records screened, 13 studies were included into the analysis. The first study was published in 1991 the latest in 2020. Eleven (n=85%) cross sectional, and two (n=15%) randomized/case-control trials were published. Sample sizes ranged between 32 and 3,986. Study sample consisted mostly of patients with depression (n=6) and general population (n=5), one study focused on health professionals and one had a combined population sample. The most common type of data collection was semi-structured interview (n=8), three studies applied paper-based self-completed questionnaires, and two collected data online by self-administrated surveys. Eleven studies (n=85%) followed a conventional TTO method. The most frequent timeframe was 10 years (n=6), while other studies set subjective life expectancy; 50 years; 80-year-old age; varying between 20-40 years; 10+10 years waiting time as a timeframe. Five out of six studies developed vignettes based on standardized scales: McSad scale (n=3), SF-12 and TooL questionnaire.

Overall, 42 different utility values occurred across the 13 studies. Seven studies elicited 17 utility values for self-experienced depression, ranging from 0.24-0.93. Six publications measured 25 utility values for five different hypothetical depression health states. Utili of hypothetical states ranged as follows: mild depression 0.66-0.91; moderate depression 0.49-0.79; severe depression 0.31-0.65 respectively.

CONCLUSIONS

So far this is the first research that systematically compared vignettes describing depression health states and catalogued TTO utility values in depression to help further economic evaluations and guide reimbursement decision making.