Development, validation, and results of a measure of 30‐day readmission following hospitalization for pneumonia

BACKGROUND: Readmission following hospital discharge has become an important target of quality improvement. OBJECTIVE: To describe the development, validation, and results of a risk-standardized measure of hospital readmission rates among elderly patients with pneumonia employed in federal quality measurement and efficiency initiatives. DESIGN: A retrospective cohort study using hospital and outpatient Medicare claims from 2005 and 2006. SETTING: A total of 4675 hospitals in the United States. PATIENTS: Medicare beneficiaries aged >65 years with a principal discharge diagnosis of pneumonia. INTERVENTION: None. MEASUREMENTS: Hospital-specific, risk-standardized 30-day readmission rates calculated as the ratio of predicted-to-expected readmissions, multiplied by the national unadjusted rate. Comparison of the areas under the receiver operating curve (ROC) and measurement of correlation coefficient in development and validation samples. RESULTS: The development sample consisted of 226,545 hospitalizations at 4675 hospitals, with an overall unadjusted 30-day readmission rate of 17.4%. The median risk-standardized hospital readmission rate was 17.3%, and the odds of readmission for a hospital one standard deviation above average was 1.4 times that of a hospital one standard deviation below average. Performance of the medical record and administrative models was similar (areas under the ROC curve 0.59 and 0.63, respectively) and the correlation coefficient of estimated state-specific standardized readmission rates from the administrative and medical record models was 0.96. CONCLUSIONS: Rehospitalization within 30 days of treatment for pneumonia is common, and rates vary across hospitals. A risk-standardized measure of hospital readmission rates derived from administrative claims has similar performance characteristics to one based on medical record review.