Causes and risk factors for rehospitalization of patients hospitalized with community-acquired pneumonia.

Background: Rehospitalization after inpatient treatment of community-acquired pneumonia occurs in one-tenth of all hospitalizations, but the clinical circumstances surrounding readmission to the hospital have not been well studied. The objective of this study was to identify the causes and risk factors for rehospitalization of inpatients with community-acquired pneumonia.

Methods: This project was performed as part of a randomized, multicenter, controlled trial of the implementation of practice guidelines to reduce the duration of intravenous antibiotic therapy and duration of hospitalization for patients who have received a clinical and radiographic diagnosis of pneumonia. The trial was conducted at 7 hospitals in Pittsburgh, Pennsylvania, from February 1998 through March 1999. The primary outcome for these analyses was rehospitalization within 30 days after the index hospitalization. Two physicians independently assigned the cause of rehospitalization as pneumonia related, comorbidity related, or both; consensus was reached for all assignments. Patient demographic characteristics and clinical factors independently associated with rehospitalization were identified using multiple logistic regression analysis.

Results: Of the 577 patients discharged after hospitalization for community-acquired pneumonia, 70 (12%) were rehospitalized within 30 days. The median time to rehospitalization was 8 days (interquartile range, 4-13 days). Overall, 52 rehospitalizations (74%) were comorbidity related, and 14 (20%) were pneumonia related. The most frequent comorbid conditions responsible for rehospitalization were cardiovascular (n = 19), pulmonary (n = 6) and neurological (n = 6) in origin. Less than a high school education (odds ratio, 2.0; 95% confidence interval, 1.1-3.4), unemployment (odds ratio, 3.7; 95% confidence interval, 1.1-12.3), coronary artery disease (odds ratio, 2.7; 95% confidence interval, 1.5-4.7), and chronic obstructive pulmonary disease (odds ratio, 2.3; 95% confidence interval, 1.3-4.1) were independently associated with rehospitalization.

Conclusions: The majority of rehospitalizations following pneumonia are comorbidity related and are the result of underlying cardiopulmonary and/or neurologic diseases. Careful attention to the clinical stability of patients with these coexisting conditions at and following hospital discharge may decrease the frequency of rehospitalization of patients with community-acquired pneumonia.