From the Institutes of Medicine (L.M.S.C., K.S., P.J., J.C.A.-A., P.-A.S., M.T., B.C.) and Health and Care Sciences (P.-A.S.), Sahlgrenska Academy at the University of Gothenburg, and Early Cardiovascular, Renal, and Metabolism (CVRM), Biopharmaceuticals Research and Development, AstraZeneca (B.C.), Gothenburg, and the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna (M.P.) - both in Sweden; and the Public Health Promotion Unit, National Institute for Health and Welfare, Helsinki (M.P.).
Obesity shortens life expectancy. Bariatric surgery is known to reduce the long-term relative risk of death, but its effect on life expectancy is unclear.
We used the Gompertz proportional hazards regression model to compare mortality and life expectancy among patients treated with either bariatric surgery (surgery group) or usual obesity care (control group) in the prospective, controlled Swedish Obese Subjects (SOS) study and participants in the SOS reference study (reference cohort), a random sample from the general population.
In total, 2007 and 2040 patients were included in the surgery group and the control group, respectively, and 1135 participants were included in the reference cohort. At the time of the analysis (December 31, 2018), the median duration of follow-up for mortality was 24 years (interquartile range, 22 to 27) in the surgery group and 22 years (interquartile range, 21 to 27) in the control group; data on mortality were available for 99.9% of patients in the study. In the SOS reference cohort, the median duration of follow-up was 20 years (interquartile range, 19 to 21), and data on mortality were available for 100% of participants. In total, 457 patients (22.8%) in the surgery group and 539 patients (26.4%) in the control group died (hazard ratio, 0.77; 95% confidence interval [CI], 0.68 to 0.87; P