title: Health insurance claims data as a means of assessing reduction in co-morbidities 6 months after bariatric surgery.
abstract: BACKGROUND
  We measured the very short-term change in obesity-related co-morbidities following bariatric surgery.
  
  
  METHODS
  Claims data were analyzed for 933 patients aged 18-62 who were covered by one of 11 New York State health plans and underwent bariatric surgery during calendar year 2002. Data covered 6 months before to 6 months after surgery. Logit regression and fixed effects logit regressions were estimated, to analyze change in the following co-morbidities after bariatric surgery: diabetes, hyperlipidemia, hypertension, asthma, sleep apnea, degenerative joint disease, gastroesophageal reflux, and depression.
  
  
  RESULTS
  There were statistically significant post-surgery decreases in each outcome studied. Controlling for individual fixed effects, the probability of a diabetes diagnosis fell by 20% after bariatric surgery. The probability of sleep apnea fell by 33%, and the probability of the other obesity-related co-morbidities fell by 11 to 19% at 6 months.
  
  
  CONCLUSIONS
  Claims data are useful for assessing changes in a wide range of co-morbidities following bariatric surgery. The data indicate significant decreases in obesity-related co-morbidities after bariatric surgery, although considerably smaller than those found in previous studies, which underscores the need for randomized controlled trials of bariatric surgery. Limitations of this study include: follow-up only at 6 months, non-experimental data, and an unknown degree of under-reporting of co-morbidities in claims data.
authors.affiliation: Department of Policy Analysis and Management and Sloan Program in Health Administration, Cornell University, Ithaca, NY 14853, USA. jhc38@cornell.edu
authors.forename: John
authors.initials: J
authors.lastname: Cawley
authors.forename: Timothy
authors.initials: T
authors.lastname: Prinz
authors.forename: Susan
authors.initials: S
authors.lastname: Beane
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D050110:Bariatric Surgery / Q000191:economics*; D015897:Comorbidity / Q000639:trends*; D005260:Female; D006801:Humans; D007348:Insurance, Health; D008297:Male; D006278:Medicare; D008875:Middle Aged; D009518:New York; D009767:Obesity, Morbid / Q000453:epidemiology / Q000601:surgery*; D011184:Postoperative Period; D012044:Regression Analysis; D014481:United States