Dysphagia and risk of aspiration pneumonia: A nonrandomized, pair-matched cohort study

Background/purpose: Dysphagia was associated with increased prevalence of aspiration pneumonia (AP) in studies that were criticized for either their small sample size or lack of prospective design. Using a considerably larger nationwide, population-based database and a long-term prospective cohort design, our study aimed to explore the relationship between dysphagia and the subsequent development of AP. Materials and methods: From 2000 to 2009, we gathered a study cohort consisting of 6979 newly diagnosed cases of dysphagia from Taiwan's National Health Insurance Research Database. For the control group, another 20,937 individuals without dysphagia were matched for age, sex, and comorbidity. The two cohorts were followed-up to observe the occurrence of AP and correlated mortality. Results: During an average of 3.88 ± 2.73 years of follow-up, we observed 315 cases of new AP [non-dysphagia (193, 0.92%) vs. dysphagia (122, 1.75%), p < 0.0001], and the incidence of AP was significant in the dysphagia group. After adjusting for age, sex, and comorbidity, dysphagia-related AP [hazard ratio (HR) 2.499; 95% confidence interval (CI), 2.089–2.99; p < 0.0001], dysphagia related mortality [HR 3.229; 95% CI, 3.052–3.417; p < 0.0001], and many other systemic diseases were independently associated with a diagnosis of AP. Conclusion: Dysphagia was highly associated with an increased risk of AP according to data derived from a large nationwide cohort database. Nonetheless, larger prospective studies or meta-analyses are recommended to confirm our findings.