Predictors of rehospitalization after admission for pneumonia in the veterans affairs healthcare system.

Introduction: Although some factors associated with rehospitalization after community-acquired pneumonia have been identified, other factors such as medical care utilization and medication usage have not been previously studied. We investigated novel predictors of rehospitalization in patients admitted with pneumonia.

Methods: Using Department of Veteran Affairs (VA) administrative data from October 2001 to September 2007, we examined a cohort of patients 65 years old and older, who were hospitalized with pneumonia, in 150 VA acute care hospitals. The cohort was randomly split into derivation and validation samples, and then logistic regression models were used to identify and validate predictors of all-cause rehospitalization within 30 days.

Results: Of the 45,134 subjects, 13% were rehospitalized within 30 days. No significant differences were noted between the derivation and validation cohorts. Factors associated with readmission included age, marital status, chronic renal disease, prior malignancy, nursing home residence, congestive heart failure, use of oral corticosteroids, number of emergency department visits a year prior, prior admission, number of outpatient clinic visits in a year prior, and length of hospital stay. The C statistics for the derivation and validation models were 0.615 and 0.613, respectively.

Conclusions: Factors associated with readmission were largely unrelated to the underlying pneumonia, but were related to demographics, comorbidities, healthcare utilization, and length of stay on index admission.