title: Predicting risk for serious complications with bariatric surgery: results from the Michigan Bariatric Surgery Collaborative.
abstract: OBJECTIVE
  To develop a risk prediction model for serious complications after bariatric surgery.
  
  
  BACKGROUND
  Despite evidence for improved safety with bariatric surgery, serious complications remain a concern for patients, providers and payers. There is little population-level data on which risk factors can be used to identify patients at high risk for major morbidity.
  
  
  METHODS
  The Michigan Bariatric Surgery Collaborative is a statewide consortium of hospitals and surgeons, which maintains an externally-audited prospective clinical registry. We analyzed data from 25,469 patients undergoing bariatric surgery between June 2006 and December 2010. Significant risk factors on univariable analysis were entered into a multivariable logistic regression model to identify factors associated with serious complications (life threatening and/or associated with lasting disability) within 30 days of surgery. Bootstrap resampling was performed to obtain bias-corrected confidence intervals and c-statistic.
  
  
  RESULTS
  Overall, 644 patients (2.5%) experienced a serious complication. Significant risk factors (P < 0.05) included: prior VTE (odds ratio [OR] 1.90, confidence interval [CI] 1.41-2.54); mobility limitations (OR 1.61, CI 1.23-2.13); coronary artery disease (OR 1.53, CI 1.17-2.02); age over 50 (OR 1.38, CI 1.18-1.61); pulmonary disease (OR 1.37, CI 1.15-1.64); male gender (OR 1.26, CI 1.06-1.50); smoking history (OR 1.20, CI 1.02-1.40); and procedure type (reference lap band): duodenal switch (OR 9.68, CI 6.05-15.49); laparoscopic gastric bypass (OR 3.58, CI 2.79-4.64); open gastric bypass (OR 3.51, CI 2.38-5.22); sleeve gastrectomy (OR 2.46, CI 1.73-3.50). The c-statistic was 0.68 (bias-corrected to 0.66) and the model was well-calibrated across deciles of predicted risk.
  
  
  CONCLUSIONS
  We have developed and validated a population-based risk scoring system for serious complications after bariatric surgery. We expect that this scoring system will improve the process of informed consent, facilitate the selection of procedures for high-risk patients, and allow for better risk stratification across studies of bariatric surgery.
authors: Department of Surgery, University of Michigan, Ann Arbor, MI, USA. jfinks@med.umich.edu
authors: Jonathan F
authors: JF
authors: Finks
authors: Kerry L
authors: KL
authors: Kole
authors: Panduranga R
authors: PR
authors: Yenumula
authors: Wayne J
authors: WJ
authors: English
authors: Kevin R
authors: KR
authors: Krause
authors: Arthur M
authors: AM
authors: Carlin
authors: Jeffrey A
authors: JA
authors: Genaw
authors: Mousumi
authors: M
authors: Banerjee
authors: John D
authors: JD
authors: Birkmeyer
authors: Nancy J
authors: NJ
authors: Birkmeyer
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008824:Michigan; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology; D018570:Risk Assessment; D012720:Severity of Illness Index