title: Hospital complication rates with bariatric surgery in Michigan.
abstract: BACKGROUND
  Despite the growing popularity of bariatric surgery, there remain concerns about perioperative safety and variation in outcomes across hospitals.
  
  
  OBJECTIVE
  To assess complication rates of different bariatric procedures and variability in rates of serious complications across hospitals and according to procedure volume and center of excellence (COE) status.
  
  
  METHODS
  Involving 25 hospitals and 62 surgeons statewide, the Michigan Bariatric Surgery Collaborative (MBSC) administers an externally audited, prospective clinical registry. We evaluated short-term morbidity in 15,275 Michigan patients undergoing 1 of 3 common bariatric procedures between 2006 and 2009. We used multilevel regression models to assess variation in risk-adjusted complication rates across hospitals and the effects of procedure volume and COE designation (by the American College of Surgeons or American Society for Metabolic and Bariatric Surgery) status.
  
  
  METHODS
  Complications occurring within 30 days of surgery.
  
  
  RESULTS
  Overall, 7.3% of patients experienced perioperative complications, most of which were wound problems and other minor complications. Serious complications were most common after gastric bypass (3.6%; 95% confidence interval [CI], 3.2%-4.0%), followed by sleeve gastrectomy (2.2%; 95% CI, 1.2%-3.2%), and laparoscopic adjustable gastric band (0.9%; 95% CI, 0.6%-1.1%) procedures (P < .001). Mortality occurred in 0.04% (95% CI, 0.001%-0.13%) of laparoscopic adjustable gastric band, 0 sleeve gastrectomy, and 0.14% (95% CI, 0.08%-0.25%) of the gastric bypass patients. After adjustment for patient characteristics and procedure mix, rates of serious complications varied from 1.6% (95% CI, 1.3-2.0) to 3.5% (95% CI, 2.4-5.0) (risk difference, 1.9; 95% CI, 0.08-3.7) across hospitals. Average annual procedure volume was inversely associated with rates of serious complications at both the hospital level (< 150 cases, 4.1%; 95% CI, 3.0%-5.1%; 150-299 cases, 2.7%; 95% CI, 2.2-3.2; and > or = 300 cases, 2.3%; 95% CI, 2.0%-2.6%; P = .003) and surgeon level (< 100 cases, 3.8%; 95% CI, 3.2%-4.5%; 100-249 cases, 2.4%; 95% CI, 2.1%-2.8%; > or = 250 cases, 1.9%; 95% CI, 1.4%-2.3%; P = .001). Adjusted rates of serious complications were similar in COE and non-COE hospitals (COE, 2.7%; 95% CI, 2.5%-3.1%; non-COE, 2.0%; 95% CI, 1.5%-2.4%; P = .41).
  
  
  CONCLUSIONS
  The frequency of serious complications among patients undergoing bariatric surgery in Michigan was relatively low. Rates of serious complications are inversely associated with hospital and surgeon procedure volume, but unrelated to COE accreditation by professional organizations.
authors.affiliation: Department of Surgery, and Center for Healthcare Outcomes and Policy, University of Michigan, Ann Arbor, MI 48104, USA. nbirkmey@umich.edu
authors.forename: Nancy J O
authors.initials: NJ
authors.lastname: Birkmeyer
authors.forename: Justin B
authors.initials: JB
authors.lastname: Dimick
authors.forename: David
authors.initials: D
authors.lastname: Share
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Hawasli
authors.forename: Wayne J
authors.initials: WJ
authors.lastname: English
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Genaw
authors.forename: Jonathan F
authors.initials: JF
authors.lastname: Finks
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Carlin
authors.forename: John D
authors.initials: JD
authors.lastname: Birkmeyer
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects*; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications / Q000453:epidemiology*