Risk factors for mortality and severe functional decline in adults with invasive pneumococcal disease: A prospective multicenter cohort study

OBJECTIVES: Invasive pneumococcal disease (IPD) is life-threatening, and survivors may experience severe functional decline. We investigated host- and pathogen-related factors associated with mortality and severe functional decline in adults with IPD. METHODS: We conducted a prospective multicenter cohort study of adults with IPD to investigate host- and pathogen-related factors associated with 30-day mortality, severe functional decline at hospital discharge among survivors, and a composite outcome of death within 30 days or severe functional decline. RESULTS: Among 664 patients with IPD, 57.5% had pneumonia, 18.7% bacteremia without focus, and 13.0% meningitis. The most frequent serotypes were 3, 19A, 22F, and 6C. Overall 30-day mortality was 19.5%, and severe functional decline occurred in 10.3% of survivors. In the primary multivariable model, older age, markers of acute severity, hospital-onset infection or residence in a long-term care facility, serotype 3, no pneumococcal vaccination within 5 years, and penicillin G MIC ≥2 µg/ml were independently associated with mortality. Among survivors, altered mental status, hypotension, and respiratory failure were independently associated with severe functional decline. For the composite outcome, host severity markers remained significant, whereas pathogen-related variables were not. CONCLUSIONS: IPD was associated with high mortality and substantial functional decline among survivors. While both host- and pathogen-related factors contributed to mortality, severe functional decline was predominantly driven by host severity markers.