Factors associated with unplanned hospital readmission among patients 65 years of age and older in a Medicare managed care plan.

PURPOSE: Unplanned hospital readmission within 30 days of discharge is considered a "sentinel event" for poor quality. Patients at high risk for this adverse event could be targeted for interventions designed to reduce their risk of readmission. The purpose of this study was to identify patient characteristics and risk factors at discharge associated with unplanned readmission within 30 days of hospital discharge. SUBJECTS AND METHODS: We performed a matched case-control study among patients in a Medicare managed care plan who had been admitted to an academic hospital. The cases were patients aged 65 years or older who were urgently or emergently readmitted to the hospital within 30 days of discharge. One control patient who was not readmitted within 30 days was matched to each case by principal diagnosis. The medical records of the first admission of the cases and the admission of the controls underwent review (blinded to case-control status) to determine the patient's baseline demographic characteristics, comorbid conditions, previous health care utilization, and functional status. The records were also reviewed to assess risk factors on discharge, including clinical instability, inability to ambulate and feed, mental status changes, number of discharge medications, and discharge disposition. RESULTS: Five factors were independently associated (P < 0.05) with unplanned readmission within 30 days. These included four baseline patient characteristics: age 80 years or older odds ratio = 1.8; 95% confidence interval (CI), 1.02-3.2], previous admission within 30 days (odds ratio = 2.3; 95% CI, 1.2-4.6), five or more medical comorbidities (odds ratio = 2.6; 95% CI, 1.5-4.7), and history of depression (odds ratio = 3.2; 95% CI, 1.4-7.9); and one discharge factor: lack of documented patient or family education (odds ratio = 2.3; 95% CI, 1.2-4.5). CONCLUSIONS: If validated, these factors may identify patients at high risk of readmission. They suggest that interventions, such as improved discharge education programs, may reduce unplanned readmission.