Bariatric surgery, compared to medical treatment, reduces morbidity at all ages but does not reduce mortality in patients aged < 43 years, especially if diabetes mellitus is present: a post hoc analysis of two retrospective cohort studies.

Bariatric surgery reduces long-term mortality in comparison with medical treatment when performed in patients aged > 43 years, but not in younger patients, where it is neutral or could even increase mortality; reduction in morbidity occurs at any age.