Risk factors for respiratory failure in pneumococcal pneumonia: the importance of pneumococcal serotypes

Pneumococcal serotypes are one of the main determinants of pneumococcal disease severity; however, data about their implication in respiratory failure are scarce. We conducted an observational study of adults hospitalised with invasive pneumococcal pneumonia to describe the host- and pathogen-related factors associated with respiratory failure. Of 1258 adults with invasive pneumococcal disease, 615 (48.9%) had respiratory failure at presentation. Patients with respiratory failure were older (62.1 years versus 55.4 years, p<0.001) and had a greater proportion of comorbid conditions. They also had a greater proportion of septic shock (41.7% versus 6.1%, p<0.001), required admission to the intensive care unit more often (38.4% versus 4.2%, p<0.001) and had a higher mortality (25.5% versus 3.5%, p<0.001). After adjustment, independent risk factors for respiratory failure were: age >50 years (OR 1.63, 95% CI 1.15-2.3), chronic lung disease (OR 1.54, 95% CI 1.1-2.15), chronic heart disease (OR 1.49, 95% CI 1.01-2.22) and infection caused by serotypes 3 (OR 1.97, 95% CI 1.23-3.16), 19A (OR 2.34, 95% CI 1.14-4.42) and 19F (OR 3.55, 95% CI 1.22-10.28). In conclusion, respiratory failure is a frequent complication of pneumococcal pneumonia and causes high morbidity and mortality. Pneumococcal serotypes 3, 19A and 19F are the main risk factors for this complication.