Health state utilities for economic evaluation of bariatric surgery : a comprehensive systematic review and meta-analysis

Health state utilities (HSUs) are health economic metrics that capture and assess health-related quality of life (HRQoL). They are essential in health-economic evaluations when calculating quality-adjusted life years. We investigated published studies reporting bariatric surgery-related HSUs elicited through direct or indirect (multiattribute utility instrument [MAUI]) patient-reported methods (PROSPERO registration number: CRD42019131725). Mean HSUs for different time points and HSU changes over time (where feasible) were meta-analysed using random-effects models. Of the 950 potentially relevant identified studies, n = 28 (2004-2018) qualified for data extraction, with n = 85 unique HSUs elicited mainly from the EQ-5D (88%). Most (75%) studies were published after 2013. The follow-up duration varied between studies and was often limited to 12 months. The pooled mean HSU was 0.72 (0.67-0.76) at baseline/presurgery (n = 18) and 0.84 (0.79-0.89) one-year postsurgery (n = 11), indicating a 0.11 (0.09-0.14) utility unit increment. EQ-5D showed the similar results. This positive difference can be partially explained by BMI and/or co-morbidities status improvement. This study provides a valuable summary of HSUs to future bariatric surgery-related cost-utility models. However, more well-designed higher-quality bariatric-related HSU studies are expected for future reviews to improve the available evidence. We suggest that researchers select an MAUI that is preferentially sensitive to the study population.