title: Hospital admission after gastric bypass: a nationwide cohort study with up to 6 years follow-up.
abstract: 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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  We found a significant risk of admission to hospital over>6 years after gastric bypass surgery.
authors.affiliation: Department of Medicine, Solna, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden. Electronic address: Gustaf.Bruze@ki.se.
authors.forename: Gustaf
authors.initials: G
authors.lastname: Bruze
authors.affiliation: Department of Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Ottosson
authors.affiliation: Department of Medicine, Solna, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Neovius
authors.affiliation: Department of Surgery, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Näslund
authors.affiliation: Division of Surgery, Departement of Clinical Sciences, Danderyds Hospital, Karolinska Institute, Stockholm, Sweden.
authors.forename: Richard
authors.initials: R
authors.lastname: Marsk
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects* / Q000706:statistics & numerical data; D005767:Gastrointestinal Diseases / Q000209:etiology / Q000601:surgery; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000601:surgery; D011182:Postoperative Care / Q000706:statistics & numerical data; D011183:Postoperative Complications / Q000209:etiology / Q000601:surgery; D012042:Registries; D012307:Risk Factors; D024162:Second-Look Surgery / Q000706:statistics & numerical data; D013548:Sweden; D055815:Young Adult