Long-term mortality of hospitalized pneumonia in the EPIC-Norfolk cohort

Abstract

SUMMARYLittle is known about cause-specific long-term mortality beyond 30 days in pneumonia. We aimed to compare the mortality of patients with hospitalized pneumonia compared to age- and sex-matched controls beyond 30 days. Participants were drawn from the European Prospective Investigation into Cancer (EPIC)-Norfolk prospective population study. Hospitalized pneumonia cases were identified from record linkage (ICD-10: J12-J18). For this study we excluded people with hospitalized pneumonia who died within 30 days. Each case identified was matched to four controls and followed up until the end June 2012 (total 15 074 person-years, mean 6·1 years, range 0·08–15·2 years). Cox regression models were constructed to examine the all-cause, respiratory and cardiovascular mortality using date of pneumonia onset as baseline with binary pneumonia status as exposure. A total of 2465 men and women (503 cases, 1962 controls) [mean age (s.d.) 64·5 (8·3) years] were included in the study. Between a 30-day to 1-year period, hazard ratios (HRs) of all-cause and cardiovascular mortality were 7·3 [95% confidence interval (CI) 5·4–9·9] and 5·9 (95% CI 3·5–9·7), respectively (with very few respiratory deaths within the same period) in cases compared to controls after adjusting for age, sex, asthma, smoking status, pack years, systolic and diastolic blood pressure, diabetes, physical activity, waist-to-hip ratio, prevalent cardiovascular and respiratory diseases. All outcomes assessed also showed increased risk of death in cases compared to controls after 1 year; respiratory cause of death being the most significant during that period (HR 16·4, 95% CI 8·9–30·1). Hospitalized pneumonia was associated with increased all-cause and specific-cause mortality beyond 30 days.