Chronic heart failure and risk of hospitalization with pneumonia: a population-based study

Eur J Intern Med. 2013 Jun;24(4):349-53. doi: 10.1016/j.ejim.2013.02.013. Epub 2013 Mar 17.


Background: Chronic heart failure may increase risk of pneumonia due to alveoli flooding and reduced microbial clearance. We examined whether chronic heart failure is a risk factor for pneumonia-related hospitalization.

Methods: In this large population-based case-control study we identified adult patients with a first-time primary or secondary discharge diagnosis of viral or bacterial pneumonia between 1994 and 2008, using health care databases in Northern Denmark. For each case, ten sex- and age-matched population controls were selected from Denmark's Civil Registration System. We used conditional logistic regression to compute relative risk (RR) for pneumonia-related hospitalization among persons with and without pre-existing heart failure, overall and stratified by medical treatment. We controlled for a wide range of comorbidities, socioeconomic markers and immunosuppressive treatment.

Results: The study included 67,162 patients with a pneumonia-related hospitalization and 671,620 population controls. The adjusted OR for pneumonia-related hospitalization among persons with previous heart failure was 1.81 (95% confidence interval (CI): 1.76-1.86) compared with other individuals. The adjusted pneumonia RR was lower for heart failure patients treated with thiazides only (adjusted OR=1.56, 95% CI: 1.46-1.67), as compared with patients whose treatment included loop-diuretics and digoxin as a marker of increased severity (adjusted OR=1.95, 95% CI: 1.85-2.06) or both loop-diuretics and spironolactone (adjusted OR=2.02, 95% CI: 1.90-2.15). The population-attributable risk of pneumonia hospitalizations caused by heart failure in our population was 6.2%.

Conclusions: Patients with chronic heart failure, in particular those using loop diuretics, have markedly increased risk of hospitalization with pneumonia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Cardiotonic Agents / therapeutic use
  • Case-Control Studies
  • Chronic Disease
  • Denmark / epidemiology
  • Digoxin / therapeutic use
  • Diuretics / adverse effects*
  • Female
  • Heart Failure / complications*
  • Heart Failure / drug therapy
  • Hospitalization / statistics & numerical data*
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Pneumonia / epidemiology
  • Pneumonia / etiology*
  • Risk Factors


  • Cardiotonic Agents
  • Diuretics
  • Digoxin