Hospital admission after gastric bypass: a nationwide cohort study with up to 6 years follow-up.

BACKGROUND: Several studies have addressed short-term admission rates after bariatric surgery. However, studies on long-term admission rates are few and population based studies are even scarcer.

OBJECTIVE: The aim of this study was to assess short- and long-term admission rates for gastrointestinal surgery after gastric bypass in Sweden compared with admission rates in the general population.

SETTING: Swedish healthcare system.

METHODS: The surgery cohort consisted of adults with body mass index≥35 identified in the Scandinavian Obesity Surgery Registry (n = 28,331; mean age 41 years; 76% women; Roux-en-Y gastric bypass performed 2007-2012). For each individual, up to 10 comparators from the general population were matched on birth year, sex, and place of residence (n = 274,513). The primary outcome was inpatient admissions due to gastrointestinal surgery retrieved from the National Patient Register through December 31, 2014. Conditional hazard ratios (HR) were estimated using Cox regression.

RESULTS: All-cause admission rates were 6.5%, 21.4%, and 65.9% during 30 days, 1 year, and 6 years after surgery, respectively. The corresponding rates for gastrointestinal surgery were 1.8%, 6.8%, and 24.4%. Compared with that of the general population, there was an increased risk of all-cause hospital admission at 1 year (HR 2.6 [2.5-2.6]) and 6 years (HR 2.7 [2.6-2.7]). The risk of hospital admission for any gastrointestinal surgical procedure was greatly increased throughout the study period (HR 8.6 [8.4-8.9]). Female sex, psychiatric disease, and low education were risk factors.

CONCLUSION: We found a significant risk of admission to hospital over>6 years after gastric bypass surgery.