Bariatric surgery decreases the number of first-time hospital admissions for cancer in severely obese patients. A retrospective analysis of the National Inpatient Sample database

Background: According to the U.S. Centers for Disease Control, cancers linked to overweight or obesity accounted for roughly 40% of all U.S. malignancies in 2014.

Objectives: The primary aim of this epidemiologic study was to assess whether bariatric surgery might have any preventative role against obesity-linked cancers among individuals with obesity.

Setting: Hospitals across the United States participating in the National Inpatient Sample database, created, updated, and monitored by the U.S. Healthcare Cost and Utilization Project.

Methods: National Inpatient Sample data collected from 2010 to 2014 were examined to identify any difference in the number of first cancer-related hospitalizations, as a proxy for cancer incidence, between patients with a history of prior bariatric surgery (cases) and those without (controls). Patients with any prior cancer diagnosis were excluded. To match the body mass index ≥35 kg/m² generally required for bariatric surgery, all controls had to have a body mass index ≥35 kg/m². International Classification of Diseases-9 codes were employed to identify admissions for 13 obesity-linked cancers. Multivariate logistic regression analysis was performed to identify any case-control differences, after matching for all baseline demographic, co-morbidity, and cancer risk-factor variables. All percentages and means (with confidence intervals) were weighted, per Healthcare Cost and Utilization Project guidelines.

Results: Among 1,590,579 controls and 247,015 bariatric surgery cases, there were 29,822 (1.93%; 95% confidence interval 1.91-1.96) and 3540 (1.43%; 1.38-1.47) first hospitalizations for cancer (adjusted odds ratio 1.17; 1.13-1.23; P < .0001).

Conclusions: Preliminary findings from a large U.S. database suggest that bariatric surgery may reduce the incidence of cancer in patients considered at high risk because of severe obesity.