Reduced risk of pneumonia and influenza infection after bariatric surgery: a retrospective cohort study among patients with nondiabetic obesity in Taiwan.

Abstract

Bariatric surgery is associated with significant improvements in immunity in individuals with obesity, but the exact efficacy in reducing pneumonia and influenza infections is unclear. To investigate the association between bariatric surgery and the risk of pneumonia and influenza infection. Nondiabetic patients who underwent bariatric surgery and matched controls were identified from the National Health Insurance Research Database of Taiwan. We identified 1648 nondiabetic patients who underwent bariatric surgery from the National Health Insurance Research Database of Taiwan in 2001-2009. These patients were matched by propensity score with 4881 nondiabetic patients with obesity who did not undergo bariatric surgery. We followed the surgical and control cohorts until death, any diagnosis of pneumonia or influenza, or December 31, 2012. The Cox proportional hazards regression model was used to calculate the relative risk of pneumonia and influenza infection in those who underwent bariatric surgery compared with those who did not. Overall, there was a .87-fold (95% CI, .78-.98) reduced risk of pneumonia and influenza infection in the surgical group versus the control group. Four years after bariatric surgery, a sustainable effect of the surgery was observed, and the risk of pneumonia and influenza infection was .83-fold reduced in the surgical group (95% CI, .73-.95). Individuals with obesity who underwent bariatric surgery had a reduced risk of pneumonia and influenza infection compared with matched control individuals. Individuals with obesity who underwent bariatric surgery had a reduced risk of pneumonia and influenza infection compared with matched control individuals.