Predicting complications after bariatric surgery using obesity-related co-morbidities

Background: To determine which (if any) pre-surgery obesity-related co-morbidities predict complications after bariatric surgery. Methods: Claims data are analyzed for 1,760 patients aged 18-62 who were covered by one of seven New York State health plans and underwent bariatric surgery during 2002-2005. Data covered 6 months before to 18 months after surgery. Pre-surgery obesity-related comorbidities studied include: diabetes, hyperlipidemia, hypertension, asthma, arthritis, sleep apnea, GERD, and depression. Specific post-surgery complications examined are: stenosis, complications associated with the anastomosis, dumping syndrome, and sepsis. Results: Obesity-related co-morbidities prior to surgery are significantly correlated with the probability of developing complications up to 180 days after bariatric surgery. For example, sepsis was significantly more likely in patients who had diabetes, arthritis, or sleep apnea prior to surgery. An additional pre-surgery comorbidity is associated with a 27.5% higher likelihood of dumping syndrome, 24.5% higher likelihood of complications associated with the anastomosis, and 23.5% higher probability of sepsis in the first 180 days after surgery. Among the individual co-morbidities studied, sleep apnea and GERD are most predictive of complications. Conclusion: Patients who exhibit multiple obesity-related co-morbidities prior to bariatric surgery are at significantly elevated risk of post-surgery complications and merit closer monitoring by health care professionals after bariatric surgery. Limitations of this study include non-experimental data and an unknown degree of under-reporting of pre-surgery co-morbidities in claims data.