Influence of comorbidities on pneumococcal community-acquired pneumonia

Background: The burden of pneumococcal pneumonia remains high in Spain despite preventive and therapeutic measures. In order to assess the population risk groups, we investigated host-related risk factors (comorbidities, etc.) and outcomes of pneumococcal community-acquired pneumonia (CAP). Methods: We compared confirmed pneumococcal pneumonia (CPP, positive culture of pleural fluid or lung samples [bronchial aspirate, BAL]), possible pneumococcal pneumonia (PPP: urinary Ag or sputum culture) and non-pneumococcal pneumonia (NPP: other aetiologies).Results: we analysed 2172 CAP(1996-2012) with known aetiology: 457(21%)CPP, 678(31%)PPP and 1037(48%)NPP. CPP showed lower rates of elderly people(>74yrs, CPP:30%, PPP:36%, NPP:36%;p<0.04) and polysaccharide pneumococcal vaccination (CPP:11%, PPP:16%, NPP:19%;p<0.01) but more hepatic disease (CPP:10%, PPP:9%, NPP:7%;p=0.04), HIV (CPP:12%, PPP:9%, NPP:5%;p<0.01). No differences were found for other comorbidities (cardiac,etc), tobacco and alcohol. CPP presented with increased severity and poorer outcomes.   CPP PPP NPP p-value PSI IV-V (%) 76 71 37 <0.01 Pulmonary complications, (%) 34 14 19 <0.01 Extrapulmonary complications, (%) 34 22 22 <0.01 ICU admission (%) 30 15 18 <0.01 Time to clinical stability, days 7.7 5.4 5.4 <0.01 Length of stay, median days 9 7 7 <0.05 1-month Mortality, (%) 13.6 5.3 9.7 <0.01 The multivariate analysis for 30d-mortality showed the following risk factors: neurological disease(OR:2.7), pulmonary complications(OR:10). Conclusions: pneumococcal CAP is still a major cause of mortality particularly in adults with comorbidities regardless of age. The conjugate pneumococcal vaccination could be a good strategy to decrease morbidity and mortality from CAP.