Objective: To determine the association between inhaled corticosteroid (ICS) use and the risk of pneumonia among Medicare patients with chronic obstructive pulmonary disease (COPD).
Methods: A nested case control analysis was performed to study the relationship between ICS use and pneumonia risk in a cohort of Medicare Advantage members with COPD. Patients were identified through a medical and pharmacy claims database. A case was designated as patient's first inpatient or outpatient pneumonia episode. Cases were matched to controls who entered the COPD cohort at the same time, but had not yet developed pneumonia by the case's index date. The association between ICS use and pneumonia was estimated using logistic regression. Adjusted models controlled for age, sex, race, use of other COPD medications, markers of COPD severity, receipt of the pneumococcal vaccine, and comorbidities. Analyses were also stratified by current or past ICS use, as well as dosage (low, medium, or high).
Results: Out of a COPD cohort of 83,455 members, 13,778 pneumonia episodes were identified; these cases were matched to 36,767 controls. Adjusting for covariates, having used any ICS during the past year was associated with increased risk of a pneumonia episode (OR 1.11, 95% CI: 1.05-1.18). Pneumonia risk was highest for current ICS users (OR 1.26, 95% CI: 1.16-1.36) and current high-dose users (OR 1.55, 95% CI: 1.25-1.92), compared to non-users.
Conclusion: As a retrospective claims analysis, this study had inherent limitations. The pneumonia diagnosis could not be confirmed, smoking history and other health confounders were not included. However, given the large study sample size and extensive number of available controls, the results remain persuasive and confirm previous studies' findings that ICS use, particularly current use and high-dose use, is associated with increased pneumonia risk.