Severe nutritional complications after bariatric surgery
Obesity , Bariatric Surgery , Gastric Bypass , Malnutrition , RYGB , Surgical Complication
Background: Severe post-operative malnutrition after bariatric surgery is believed to be very rare, but little is known about its incidence and risk factors. Post-surgical follow-up attendance at a bariatric centre reduces the risk of many bariatric surgery-related complications, but its impact on the occurrence of severe post-operative malnutrition has not been studied. Aims: 1) Describe incidence and factors associated with severe nutritional complications following bariatric surgery. 2) Investigate the relationship between attending follow-up during the first post-surgical year after Roux-en-Y gastric bypass (RYGB) and severe nutritional complications. Methods: Retrospective population-based cohort study of Ontario adults undergoing bariatric surgery from 2009 to 2015. The primary outcome was a severe nutritional complication, defined as hospital admission with malnutrition. Patient, institution, and surgical factors were obtained from administrative databases and the Ontario Bariatric Registry (OBR). In the first study, we describe incidence and patterns of severe nutritional complications after bariatric surgery, including association with other post-surgical complications, mortality patterns and healthcare use. In the second study, we examine the relationship between follow-up at a bariatric centre during the first year after surgery, and occurrence of the primary outcome after the first year using Cox Proportional Hazards multivariable modeling in patients who had RYGB and participated in OBR. Datasets were linked and analyzed at ICES Queen’s. Results: 18,783 Ontario adults underwent bariatric surgery during the study period (88.8% RYGB). Mean age was 45.1 years, 81.8% were female and 57.1% participated in the OBR. 2% of the cohort had severe nutritional complications, with an incidence rate of 4.5 per 1000 person-years of follow-up. Risk was constant over time. Factors associated with severe nutritional complication included more major comorbidities, post-surgical complication, and imperfect follow-up. 9105 patients met inclusion criteria for the second study. Compared to patients with perfect follow-up, those with no follow-up (HR 3.09) and partial follow-up (HR 1.94) had significantly increased risk of severe nutritional complications. Conclusions: Severe nutritional complications after bariatric surgery occur at rates similar to many bariatric surgery-specific complications. Adherence to follow-up during the first year after RYGB is independently associated with a reduction in risk of subsequent severe nutritional complications.