Unilateral Vocal Fold Paralysis and Risk of Pneumonia: A Nationwide Population-Based Cohort Study

Objective. To investigate pneumonia risk among patients with unilateral vocal fold paralysis (UVFP). Study Design. Retrospective population-based cohort study. Setting. This study used data from the National Health Insurance Research Database of Taiwan, a nationwide population-based database. Subjects and Methods. A total of 419 patients newly diagnosed with UVFP between January 1, 1997, and December 31, 2013, were identified from the Longitudinal Health Insurance Database 2000, a nationally representative database of 1 million randomly selected patients. Moreover, 1676 patients without UVFP were matched to patients with UVFP at a 1: 4 ratio based on age, sex, socioeconomic status, urbanization level, and site-specific cancers. Patients were followed up until death or the end of the study period (December 31, 2013). The primary outcome was the occurrence of pneumonia. Results. The cumulative incidence of pneumonia was significantly higher for patients with UVFP than those without UFVP (P < .001). The adjusted Cox proportional hazard model showed that UVFP was significantly associated with a higher incidence of pneumonia (hazard ratio, 1.97; 95% CI, 1.35-2.86; P < .001). Subgroup analyses demonstrated that UVFP was an independent risk factor of pneumonia for 4 subgroups: young (18-50 years), older (>= 51 years), male, and cancer. Conclusion. This is the first nationwide population-based cohort study to investigate the association between UVFP and pneumonia. The findings indicate that UVFP is an independent risk factor of pneumonia. Given the study results, physicians should be aware of the potential for pneumonia occurrence following UVFP.