Risk of exacerbation following pneumonia in adults with heart failure or chronic obstructive pulmonary disease

BACKGROUND Recent evidence demonstrates increased short-term risk of cardiac complications and respiratory failure among patients with heart failure (HF) and chronic obstructive pulmonary disease (COPD), respectively, concurrent with an episode of community-acquired pneumonia (CAP). We evaluated patients with pre-existing HF or COPD, beginning 30 days after CAP diagnosis, to determine if CAP had a prolonged impact on their underlying comorbidity. METHODS A retrospective matched-cohort design using US healthcare claims was employed. In each month of accrual, patients with HF or COPD who developed CAP ("CAP patients") were matched (1:1, without replacement, on demographic and clinical profiles) to patients with HF or COPD who did not develop CAP ("comparison patients"). All patients were aged ≥40 years, and were pneumonia free during prior 1-year period. Exacerbation beginning 30 days after the CAP diagnosis and for the subsequent 1-year period were compared between CAP and comparison patients. FINDINGS 38,010 (4·6%) HF patients and 48,703 (5·9%) COPD patients experienced a new CAP episode requiring hospitalization or outpatient care only, and were matched to comparison patients. In the HF subset, CAP patients were 47·2% more likely to experience an exacerbation vs patients without CAP (17·8% vs. 12·1%; p<0·001); in the COPD subset, CAP patients were 42·3% more likely to experience an exacerbation (16·2% vs. 11·4%; p<0·001). CONCLUSIONS Our data provide evidence that CAP foreshadows a prolonged increase in risk of exacerbation of underlying HF or COPD in adults, and suggests a potential benefit to CAP prevention strategies.