Mortality and readmission in the year following hospitalization for pneumonia among US adults.

Abstract Background Increasing evidence suggests the impact of pneumonia persists beyond hospital discharge and the acute phase of respiratory symptoms. We characterized short-term and long-term risks of mortality and hospital readmission across the adult age span and spectrum of comorbidities. Methods Retrospective cohort design and Optum's de-identified Integrated Claims-Clinical dataset (2012–2018) were employed. Study population comprised adults who had ≥1 pneumonia hospitalization; each hospitalization ≥365 days apart was considered. Cumulative risks of all-cause mortality (from pneumonia hospitalization through 360-day post-discharge period) and all-cause hospital readmission (during 360-day post-discharge period) were summarized on an overall basis as well as by age and comorbidity profile (i.e., healthy, at-risk, high-risk). Results Study population totaled 37,006 patients who contributed 38,809 pneumonia hospitalizations; mean age was 71 years, 51% were female, and 88% had at-risk (33%) or high-risk (55%) conditions. Mortality was 3.5% in hospital, 8.2% from admission to 30 days post-discharge, and 17.7% from admission to 360 days post-discharge. Hospital readmission was 12.5% during the 30-day post-discharge period, and 42.3% during the 360-day post-discharge period. Mortality risk increased with age and severity of comorbidity profile; readmission risk was highest for persons aged 65–74 years and persons with high-risk conditions. Conclusions All-cause mortality up to 1 year following pneumonia hospitalization was substantial, and was associated with increasing age and worsening comorbidity profile. Both readmission and mortality were greater at all ages in at-risk and high-risk subgroups (vs. healthy counterparts). Strategies that prevent pneumonia and/or associated pathophysiologic changes, especially among individuals with comorbidities, have the potential to reduce morbidity and mortality.