Risk Factors for Pneumonia and the Effect of the Pneumococcal Vaccine in Patients With Chronic Airflow Obstruction.

To evaluate the risk factors for pneumonia and the efficacy of the pneumococcal polysaccharide vaccine (PPV) in patients with chronic airflow obstruction. We retrospectively studied the risk factors for pneumonia in 820 consecutive patients with chronic obstructive pulmonary disease (COPD) (n=509) and patients with asthma-COPD overlap syndrome (ACOS) (n=311). The effects of asthma, age, smoking history, chronic sputum, use of inhaled corticosteroids, percent predicted forced vital capacity (%FVC), percent predicted forced expiratory volume in 1 second (%FEV), body mass index (BMI), computed tomography (CT)-diagnosed emphysema, and the pneumococcal vaccination on the frequency of pneumonia were assessed. There was no difference in the frequency of pneumonia in patients with COPD and those with ACOS. In a univariate analysis, age (= 0.031), %FVC (< 0.001), %FEV ( < 0.001), BMI ( = 0.003), the presence of emphysema ( < 0.001) and a history of vaccination with the PPV ( = 0.034) were associated with the frequency of pneumonia. A multivariate analysis identified low BMI, the presence of emphysema and the absence of a pneumococcal vaccination as independent risk factors. The combination index of these factors, the BOVE index, which is calculated from low BMI (<22 kg/m), low %FEV (<60%), vaccination history and emphysema was associated with the overall frequency of pneumonia. The index of multidimensional risk factors is useful to predict the frequency of pneumonia in patients with chronic airflow obstruction. The pneumococcal vaccination was associated with significantly lower incidence of pneumonia.