title: Clinical outcomes after bariatric surgery: a five-year matched cohort analysis in seven US states.
abstract: BACKGROUND
  Bariatric surgery is the most effective weight loss treatment, yet few studies have reported on short- and long-term outcomes postsurgery.
  
  
  METHODS
  Using claims data from seven Blue Cross/Blue Shield health plans serving seven states, we conducted a non-concurrent, matched cohort study. We followed 22,693 persons who underwent bariatric surgery during 2003-2007 and were enrolled at least 6 months before and after surgery. Using logistic regression, we compared serious and less serious adverse clinical outcomes, hospitalizations, planned procedures, and obesity-related co-morbidities between groups for up to 5 years.
  
  
  RESULTS
  Relative to controls, surgery patients were more likely to experience a serious [odds ratio (OR) 1.9; 95% confidence interval (CI) 1.8-2.0] or less serious (OR 2.5, CI 2.4-2.7) adverse clinical outcome or hospitalization (OR 1.3, CI 1.3-1.4) at 1 year postsurgery. The risk remained elevated until 4 years postsurgery for serious events and 5 years for less serious outcomes and hospitalizations. Some complication rates were lower for patients undergoing laparoscopic surgery. Planned procedures, such as skin reduction, peaked in postsurgery year 2 but remained elevated through year 5. Surgery patients had a 55% decreased risk of obesity-related co-morbidities, such as type 2 diabetes, in the first year postsurgery, which remained low throughout the study (year 5: OR 0.4, CI 0.4-0.5).
  
  
  CONCLUSIONS
  While bariatric surgery is associated with a higher risk of adverse clinical outcomes compared to controls, it also substantially decreased obesity-related co-morbidities during the 5-year follow-up.
authors.affiliation: Center for Health Care Research and Policy, Department of Medicine, MetroHealth Medical Center/Case Western Reserve University, 2500 MetroHealth Drive, Rammelkamp building R234A, Cleveland, OH 44109, USA. goldenberg_5@yahoo.com
authors.forename: Shari Danielle
authors.initials: SD
authors.lastname: Bolen
authors.forename: Hsien-Yen
authors.initials: HY
authors.lastname: Chang
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Weiner
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Richards
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Shore
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Goodwin
authors.forename: Roger A
authors.initials: RA
authors.lastname: Johns
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Magnuson
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D050110:Bariatric Surgery / Q000009:adverse effects / Q000379:methods; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000453:epidemiology / Q000534:rehabilitation / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D015431:Weight Loss; D055815:Young Adult