Decreased Long-Term Respiratory Infection Risk After Bariatric Surgery: a Comprehensive National Cohort Study.

Purpose: This study aims to determine whether bariatric surgery (BS) decreases the risk of respiratory tract infections (RTIs) in obese patients.
Materials and Methods: This retrospective, population-based, matched cohort study utilized data from the Taiwan National Health Insurance Research Database. All patients 18 to 55 years of age with obesity diagnosed between 2005 and 2010 were enrolled. Patients were separated into two groups based on whether they underwent BS. Two groups were selected using 1:1 propensity score matching according to age, sex, and comorbidities. The general population was also enrolled for comparison. The primary endpoint was the incidence of RTIs, including pneumonia, influenza, and bronchitis. All patients were followed up until the end of 2013, the primary endpoint, or death.
Results: Compared to the non-surgery group, the BS group was at significantly lower risk for RTIs (aHR 0.432, 95% CI 0.340-0.549, p < 0.001) with shorter length of hospital stay (LOH) and lower cost. Regardless of the RTI-related mortality, pneumonia, influenza, and bronchitis rates, BS did have significant protective effects on the non-surgery group. Compared to the general population, the BS group was at higher risk for RTIs (aHR 3.601, 95% CI 2.742-4.728, p < 0.001) with similar LOH and lower cost.
Conclusion: Patients with obesity who underwent BS were at significantly lower risk for RTIs than obese patients who did not undergo BS but were at higher risk for RTIs than the general population. BS may result in a long-term reduction of the RTI risk.