Incremental risk of long-term mortality with increased burden of comorbidity in hospitalized patients with pneumonia

Background: Patients hospitalized for pneumonia often have concurrent comorbid conditions (CCs). The influence of CCs on the risk of subsequent death is not fully understood. Methods: We examined adults hospitalized for pneumonia between 1996 through 2015 at Mayo Clinic for the presence of 20 priori selected CCs. We estimated cumulative all-cause mortality by number of CCs using multivariable Cox regression model. Results: Study comprised of 9580 adults (age 70 ± 17.0 years, men 53%, whites 88%) with median number of CCs 3 (interquartile 1–4), and overall deaths 6032 (62.9%) during 50,934 person-years of follow up (118.5 deaths/1000 person-years). After adjustment, any single comorbid condition was associated with 9% greater risk of death (95% confidence interval 1.08–1.11, P < 0.0001). When study cohort was stratified according to number of comorbidities (none, 1, 2, 3, 4, 5, and ≥6 CCs), the risk of death increased as the number of CCs increased (33 for no CCs vs 252 deaths for ≥6 CCs per 1000 person-years). Conclusions: Long-term mortality after hospitalization for pneumonia increases as the burden of comorbidities increases. Therefore, a simple comorbidity count help improve prognostic accuracy in identifying patients at increased risk of death following an episode of pneumonia.