Risk of pneumonia in patients with gastroesophageal reflux disease: A population-based cohort study

PURPOSE The prevalence of gastroesophagel reflux disease (GERD) has steadily increased. However, the association between GERD itself and the risk of pneumonia remains unclear. This study aimed to investigate the association between GERD and long-term risk of pneumonia and to identify the major risk factors for pneumonia in GERD patients. METHODS Using the Taiwan National Health Insurance Research Database, we identified patients who were newly diagnosed with GERD and treated with proton pump inhibitors (PPIs) from January 1, 2004 through December 31, 2010. Two groups comprising 15,715 GERD cases and 15,715 non-GERD matched controls were generated using propensity score matching, thereby making the differences in basic demographics, concomitant medication use, and comorbidities between the two groups inconsiderable. RESULTS Cumulative incidence of pneumonia was significantly higher in the patients with GERD than that in the non-GERD matched controls, with an adjusted HR of 1.48 (95% confidence interval [CI] = 1.31-1.67; P < 0.001) within 6-year follow-ups. Multivariate stratified analyses revealed similar results in many subgroups, with a highest risk in individuals younger than 40 years of age (HR = 2.17, 95% CI = 1.48-3.19). Crucially, patients with GERD using PPIs longer than 4 months were at a significantly increased risk of pneumonia than those who did not use PPIs or took PPIs less than 4 months. CONCLUSIONS GERD was significantly associated with long-term risk of pneumonia, especially in GERD with PPI use longer than 4 months or in the young population. Further prospective longitudinal studies should be conducted for validation and implementing clinical practice guidelines.