Predicting hospital readmission: different approaches raise new questions about old issues.

Readmission to an acute-care hospital within a short period of time after discharge may be because of unexpected deterioration in a patient’s condition; however, it could also reflect inadequate care during the initial admission, premature discharge, or absence of planning for transition to community care. Avoidable readmissions impair patient health and safety and cause substantial waste of health system resources. A study on Medicare beneficiaries hospitalized during 2003–2004 found that 20% had been rehospitalized within 30 days and 34% by 90 days. By 1 estimate, 20%–25% of readmissions are potentially avoidable. The proportion of readmissions that occur within a specified period such as 30 days has long been seen as a potential metric for hospital quality of care. Payers could identify institutions with excessive rates of readmission relative to peers and impose financial penalties such as reduced reimbursement. Simple ratios are clearly inadequate for this purpose because hospital case mix differs; an inner-city hospital serving the urban poor might have a high rate of unavoidable readmissions compared with a facility in an affluent suburb. Constructing an adjusted ratio on the basis of the administrative data required for claims processing is no simple matter. However, that is a key element of an important provision in the Affordable Care Act, the Hospital Readmissions Reduction Program. As of October 2012, Medicare will calculate excess all-cause readmission ratios to adjust payment for 3 common and costly discharge diagnoses: acute myocardial infarction, heart failure, and pneumonia. In this edition of Medical Care, Hockenberry et al investigate 2 fundamental questions underlying the new payment policy. Do historic hospital readmission rates predict risk-adjusted patient readmission? How is the cost of a readmission related to cost of the initial admission? For their analysis, Hockenberry and colleagues utilized data from the Veterans Health Administration (VHA). Like the nation’s civilian health care systems, the VHA provides comprehensive inpatient and outpatient services across a broad spectrum of acute and chronic diseases. However, VHA patients receive care in an environment in which the organizational structure and financial incentives are substantially different than for most Medicare beneficiaries. Hospitals are funded through annual budgets, whereas most physicians are in effect salaried employees. Because of the VHA’s inability to utilize economic incentives to reduce rehospitalization, VHA managers are focusing on data-driven performance measurement coupled with treatment protocols that ensure continuity of care. Absence of fee-for-service financial incentives makes the VHA a unique setting to study determinants of readmission. Statistical analysis of rates of readmission is complex and necessitates many decisions on variable selection and specification of the regression model. As a counterpoint to the article by Hockenberry and colleagues, we present a commentary by Pizer who critiques the methodology and questions the validity of study findings. Following is a