Risk of suicide and non-fatal self-harm after bariatric surgery: results from two matched cohort studies

Abstract

SUMMARYBACKGROUNDBariatric surgery reduces mortality, but may have adverse effects on mental health. We assessed suicide risk after surgical compared to nonsurgical obesity treatment.METHODSSuicide and nonfatal self-harm events retrieved from nationwide Swedish registers were examined in two cohorts. The nonrandomised prospective Swedish Obese Subjects (SOS) study compares bariatric surgery (n=2010; 1369 vertical-banded gastroplasty, 376 gastric banding, 265 gastric bypass) with usual care (n=2037; recruitment 1987–2001). The second cohort comprises individuals from the Scandinavian Obesity Surgery Registry (SOReg; n=20,256 gastric bypass patients) matched to individuals treated with intensive lifestyle modification (n=16,162; intervention 2006–2013) on baseline BMI, age, sex, education level, diabetes, cardiovascular disease, history of self-harm, substance abuse, antidepressant use, anxiolytics use, and psychiatric healthcare contacts.FINDINGSDuring 68,528 person-years (median 18; interquartile range 14–21) in SOS, there were 87 versus 49 suicides or nonfatal self-harm events in the surgery and control groups (adjusted hazard ratio [aHR] 1.78 [95%CI 1.23–2.57]; P=0.0021), of which 9 and 3 were suicides (3.06 [0.79–11.9]; P=0.107). In analyses by primary procedure type, increased risk of suicide or nonfatal self-harm was observed for gastric bypass (aHR 3.48 *1.65–7.31+; P=0.0010), gastric banding (2.43 *1.23–4.82+; P=0.011) and vertical-banded gastroplasty compared to controls (2.25 *1.37–3.71+; P=0.0015). Out of 9 deaths by suicide in the SOS surgery group, 5 occurred after gastric bypass (2 primary and 3 converted procedures). During 149,582 person-years (median 3.9; interquartile range 2.8–5.2), there were 341 suicides or nonfatal self-harm events in the SOReg gastric bypass group and 84 in the intensive lifestyle group (aHR 3.16 [2.46–4.06]; P<0.0001), of which 33 and 5 were suicides (5.17 [1.86–14.4]; P=0.0017). In SOS, substance abuse was recorded in 48% (39/81) of surgery patients and 28% (13/47) of controls with nonfatal self-harm events (P=0.023). The corresponding percentages for SOReg gastric bypass and intensive lifestyle participants were 51% (162/316) versus 29% (23/80; P=0.0003).INTERPRETATIONBariatric surgery was associated with suicide and nonfatal self-harm. Although the absolute risks were low, the findings indicate a need for post-operative psychiatric surveillance and patient information before surgery regarding self-harm.FUNDINGUS National Institutes of Health and Swedish Research Council