The Impact of Pre-existing Heart Failure on Pneumonia Prognosis: Population-based Cohort Study

Background  There are limited data describing how pre-existing heart failure affects mortality following pneumonia. Objective  To examine the association between history and severity of heart failure and mortality among patients hospitalized for pneumonia. Design  Population-based cohort study in Western Denmark between 1994 and 2003. Patients  33,736 adults with a first-time hospitalization for pneumonia. Heart failure was identified and categorized based on data linked from population-based health care databases. Measurements  We compared 30-day mortality between patients with pre-existing heart failure and other pneumonia patients, while adjusting for age, gender, comorbidity, and medication use. Results  The 30-day mortality was 24.4% among heart-failure patients and 14.4% among other patients, with an adjusted 30-day mortality rate ratio (MRR) of 1.40 (95% CI: 1.29–1.51). Adjusted MRRs increased according to severity of pre-existing heart failure, as indicated by medication regimen: thiazide-based, MRR = 1.09 (95% CI: 0.79–1.50); loop-diuretics, MRR = 1.25 (95% CI: 1.10–1.43); loop-diuretics and digoxin, MRR = 1.35 (95% CI: 1.18–1.55); loop-diuretics and spironolactone, MRR = 1.72 (95% CI: 1.49–2.00). Pre-existing heart valve disease and atrial fibrillation substantially increased mortality. Conclusion  History and severity of heart failure are associated with a poor outcome for patients hospitalized with pneumonia.