Background: Patients recently hospitalized for community-acquired pneumonia (CAP) are more likely to be readmitted to the hospital. Baseline comorbidities are believed to be contributing factors, but it is unknown whether factors such as CAP-related deterioration during hospitalization also contribute to readmission. Capelastegui and colleagues conducted a prospective observational study of adult patients who were consecutively hospitalized for CAP.

The Study: Patients were excluded from the study if they tested positive for human immunodeficiency virus infection, were chronically immunosuppressed, had been hospitalized recently for other reasons, or were nursing home residents. Baseline demographic information was collected, as was information on prehospitalization functional status. Data from the initial hospitalization were also gathered, including treatment failure (e.g., hemodynamic instability, respiratory failure, radiologic progression of pneumonia) and the presence of comorbid conditions. The primary outcome was readmission within 30 days after discharge.

Results: Of the 1,117 consecutively hospitalized patients who survived an initial admission for CAP, 81 (7.2 percent) were readmitted within 30 days of discharge. Approximately 36 percent of readmissions were pneumonia-related, with the remainder of patients being hospitalized for unrelated reasons (e.g., congestive heart failure, gastrointestinal bleeding).

Pneumonia-related readmissions were associated with initial CAP treatment failure (hazard ratio [HR] = 2.9), or having at least one instability factor present at discharge (i.e., temperature of 99.0°F [37.2°C] or greater, heart rate of 120 or more beats per minute, respiratory rate of 24 or more breaths per minute, systolic blood pressure of 90 mm Hg or less, or an oxygen saturation rate of less than 90 percent on room air; HR for at least one factor = 2.8). Patients with at least two risk factors were even more likely to be readmitted (HR = 9.0).

In contrast, readmissions unrelated to pneumonia were associated with being 65 years and older (HR = 4.5) or having a decompensation of a comorbidity during the initial hospitalization for CAP (HR = 3.5). Having two of these risk factors was also associated with greater risk of readmission (HR = 5.3).

Conclusion: Different risk factors appear to play a role in readmissions related to pneumonia and those that are unrelated after an initial hospitalization for CAP. The authors suggest that effectively treating comorbidities during an initial hospitalization, as well as ensuring that patients are not discharged while exhibiting any instability factors, could be useful in preventing hospital readmissions.