Preoperative depression and outcomes after metabolic and bariatric surgery: A systematic narrative review

Preoperative depression is prevalent among patients undergoing metabolic and bariatric surgery (MBS) and is a potentially modifiable risk factor. However, the impact of preoperative depression on MBS outcomes has not been systematically reviewed. A search of MEDLINE, Embase, Cochrane, and PsychINFO (inception to June 2023) was conducted for studies reporting associations between preoperative depression and any clinical or patient-reported outcomes after MBS. Eighteen studies (5 prospective and 13 retrospective) reporting on 5933 participants were included. Most participants underwent gastric bypass or sleeve gastrectomy. Meta-analyses were not conducted due to heterogeneity in reported outcomes; findings were instead synthesized using a narrative and tabular approach. Across 13 studies (n = 3390) the associations between preoperative depression and weight loss outcomes at 6-72 months were mixed overall. This may be related to differences in cohort characteristics, outcome definitions, and instruments used to measure depression. A small number of studies reported that preoperative depression was associated with lower quality of life, worse acute pain, and more perioperative complications after surgery. Most of the included studies were deemed to be at high risk of bias, resulting in low or very low certainty of evidence according to the Risk of Bias In Non-randomized Studies - of Exposure (ROBINS-E) tool. While the impact of preoperative depression on weight loss after MBS remains unclear, there is early evidence that depression has negative consequences on other patient-important outcomes. Adequately powered studies using more sophisticated statistical methods are needed to accurately estimate these associations.