title: The combined effect of age and body mass index on outcomes in foregut surgery: a regression model analysis of the National Surgical Quality Improvement Program data.
abstract: In a parallel demographic phenomenon, the elderly and obese populations will become a larger part of our population and surgical practices. The elderly obese surgical risk profile is not clearly defined, although studies have confirmed their independent negative effect on surgical outcomes. Benign foregut surgery is a relatively common complex procedure performed on this demographic and warrants deeper investigation into outcomes. We investigate the synergistic effect of age and body mass index (BMI) on the outcomes of benign foregut surgery.
  
  
  
  Data from National Surgical Quality Improvement Program were collected for all patients undergoing foregut surgery from 2005 to 2012. Subjects were over 18 years of age and 16 BMI. Primary and secondary outcomes were 30-day mortality and overall 30-day morbidity, respectfully. Binary logistic regression models were used to assess independent and interactive effects of age and BMI.
  
  
  
  A total of 19,547 patients had an average age and BMI of 57 and 29.7, respectively. Sample 30-day mortality was 0.32 %. Every 10-year age increase led to a 46 % increased odds of mortality. BMI showed a bimodal distribution with underweight and morbidly obese patients having increased mortality. The effect of BMI only became apparent with increasing age.
  
  
  
  Both age and BMI are independent predictors of mortality; only older patients experienced the bimodal BMI effect. Therefore, increasing age and BMI have a synergistic effect on outcomes after foregut operations.
authors.affiliation: School of Public Health, Rutgers Biomedical and Health Sciences, Rutgers University, Newark, NJ, USA.
authors.forename: Prashanth
authors.initials: P
authors.lastname: Palvannan
authors.affiliation: Department of Surgery, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Rutgers University, 185 South Orange Avenue, Suite MSB G530, Newark, NJ, 07103, USA.
authors.forename: Irving
authors.initials: I
authors.lastname: Miranda
authors.affiliation: Department of Surgery, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Rutgers University, 185 South Orange Avenue, Suite MSB G530, Newark, NJ, 07103, USA. Aziz.merchant@rutgers.edu.
authors.forename: Aziz M
authors.initials: AM
authors.lastname: Merchant
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D016208:Databases, Factual; D013505:Digestive System Surgical Procedures / Q000009:adverse effects* / Q000401:mortality*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications; D011183:Postoperative Complications / Q000453:epidemiology; D012307:Risk Factors; D013851:Thinness / Q000150:complications; D014481:United States / Q000453:epidemiology; D041742:Upper Gastrointestinal Tract / Q000601:surgery*
keywords: Age; Foregut surgery; Obesity; Regression modeling