Impact of pneumococcal vaccination on pneumonia rates in patients with COPD and asthma

BACKGROUND: Patients with chronic obstructive pulmonary disease ( COPD) are included in several national pneumococcal vaccination recommendations whereas asthma patients are not. The objective of this study was to evaluate pneumonia-related hospitalization risk in patients with COPD or asthma and vaccination impact. METHODS: We identified patients with documented pneumococcal vaccination from a cohort of veterans with either a diagnosis of asthma or COPD and their matched controls. Patients were identified between October 1, 1997 and September 30, 1998 and followed for 5 years. For each group we identified pneumococcal pneumonia hospitalizations and all pneumonia-related hospitalizations in the periods before and after vaccination. We estimated hospitalization rates and compared rates in the asthma and COPD groups to controls using negative binomial regression models. RESULTS: We identified 16,074 COPD patients (average age 65.8 years), 14,028 controls for the COPD patients (average age 67.5 years), 2,746 asthma patients (average age 53.0 years), and 1,345 controls for the asthma patients (average age 59.2 years). Compared to controls, the adjusted risk of pneumococcal pneumonia hospitalizations before pneumococcal vaccination was COPD= 8.02 (95% CI, 4.44-14.48) and asthma= 0.76 (0.17-3.53). For any pneumonia-related hospitalization, the adjusted risk was COPD= 3.91 (3.40-4.50) and asthma= 1.45 (0.85-2.46). After vaccination, events decreased in all groups. The adjusted risk for pneumococcal pneumonia hospitalizations postvaccination was COPD= 3.87 (2.55-5.88) and asthma= 0.30 (0.04- 1.99). For any pneumonia-related hospitalization the adjusted risk was COPD= 3.71 (3.33-4.13) and asthma= 0.79 (0.50-1.25). CONCLUSIONS: This study supports the value of vaccinating COPD patients; however, the value of vaccination for asthma patients is less certain.