One-year outcomes of community-acquired and healthcare-associated pneumonia in the Veterans Affairs Healthcare System

Abstract

Background: While studies have demonstrated higher medium-term mortality for community-acquired pneumonia (CAP), mortality and costs have not been characterized for healthcare-associated pneumonia (HCAP) over a 1-year period.

Methods: We conducted a retrospective cohort study to evaluate mortality rates and health system costs for patients with CAP or HCAP during initial hospitalization and for 1 year after hospital discharge. We selected 50 758 patients admitted to the Veterans Affairs (VA) healthcare system between October 2003 and May 2007. Main outcome measures included hospital, post-discharge, and cumulative mortality rates and cost during initial hospitalization and at 12 months following discharge.

Results: Hospital and 1-year HCAP mortality were nearly twice that of CAP. HCAP was an independent predictor for hospital mortality (odds ratio (OR) 1.62, 95% confidence interval (CI) 1.49-1.76) and 1-year mortality (OR 1.99, 95% CI 1.87-2.11) when controlling for demographics, comorbidities, pneumonia severity, and factors associated with multidrug-resistant infection, including immune suppression, previous antibiotic treatment, and aspiration pneumonia. HCAP patients consistently had higher mortality in each stratum of the Charlson-Deyo-Quan comorbidity index. HCAP patients incurred significantly greater cost during the initial hospital stay and in the following 12 months. Demographics and comorbid conditions, particularly aspiration pneumonia, accounted for 19-33% of this difference.

Conclusion: HCAP represents a distinct category of pneumonia with particularly poor survival up to 1 year after hospital discharge. While comorbidities, pneumonia severity, and risk factors for multidrug-resistant infection may interact to produce even higher mortality compared to CAP, they alone do not explain the observed differences.

Figure 1

Selection of Hospital Stays * Includes decompensated chronic obstructive pulmonary disease with acute exacerbation (491.21), asthma (493.9), food/vomitus pneumonitis (507), acute respiratory failure (518.81), acute respiratory distress (518.82), or other respiratory distress/insufficiency (786.09).

Figure 2

Kaplan-Meier Survival Curves by HCAP Status and Comorbidity Score* Notes: CAP= Community-acquired pneumonia; HCAP=Health-care-associated Pneumonia; CDQ = Charlson-Deyo-Quan comorbidity index score * All HCAP-CAP comparisons were significant (p<.05) by log-rank test.