Figure 3.

Cox proportional hazard model adjusted for baseline age, sex, forced expiratory volume 1% predicted, and baseline smoking status, showing the time to first acute exacerbation in the 2 vaccine groups. No difference between 7-valent diphtheria-60 protein conjugated pneumococcal vaccine and 23-valent pneumococcal polysaccharide vaccine was observed (hazard ratio, 0.91; P = .66). Abbreviations: COPD, chronic obstructive pulmonary disease; PCV7, 7-valent diphtheria-60 protein conjugated pneumococcal vaccine; PPSV23, 23-valent pneumococcal polysaccharide vaccine.