Risk-adjusted 30-day readmission rates are not associated with in-hospital quality of care

Quality of care in hospital does appear to affect long-term outcomes

Ambarish Pandey (Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, USA) and others report in JAMA Cardiology that risk-adjusted 30-day readmission rates after myocardial infarction are not associated with in-hospital quality of care or clinical outcomes after the first 30 days after discharge. This finding, the authors say, has implications because US hospitals are penalised if they have a higher than expected risk-adjusted 30-day readmission rate.

Pandey et al comment that previous studies, among patients with acute myocardial infarction, have found “variable associations” between in-hospital care quality and short-term clinical outcomes. They add: “However, data on relationships between the Centers for Medicare and Medicaid Services (CMS)-determined 30-day readmission performance metric and objective measures of care quality and long-term clinical outcomes for myocardial infarction are lakcing.”

Therefore, the authors reviewed data from the NCDR ACTION Registry-Get With the Guidelines (GWTG) to evaluate the association (if any) between 30-day myocardial infarction readmission rates and measures of in-patient care quality and one-year clinical outcomes. Process of care outcomes included adherence to individual myocardial infarction acute and discharge performance measures while clinical outcome measures included days from discharge to the composite of all-cause mortality or all-cause readmission within one-year of discharge.

Of 380 hospitals in the study (with 176,644 patients), 42.9% had higher than expected 30-day readmission rates for myocardial infarction (MI-ERR >1). “Compared with centres with MI-ERR less than or equal to 1, the proportion of black patients was higher among hospital groups with MI-ERR greater than 1 (7.6% vs. 4.5%; p=0.01),” Pandey et al say. However, they note that they found no significant association between MI-ERR and measures of care quality for myocardial infarction during the index hospitalisation, adding that “MI-ERR was not significantly associated with mortality risk at one-year follow-up after adjustment for potential confounders”. While higher MI-ERR was associated with greater risk for one-year all-cause readmission, this association was driven by readmissions that occurred soon after hospitalisation.

As to why there was no apparent correlation between readmission rates and in-hospital quality of care, the authors suggest several reasons. They write: “First, the overall adherence to process of care measures among NCDR ACTION Registry-GWTG-participating hospitals is very high. Thus, there could be a ‘ceiling effect’ limiting our ability to identify an association between MI-ERR and quality of care metrics. Second, the association between hospital-level quality of care and readmission risk is stronger over the first few days after discharge and declines significantly by 30 days. Third, 30-day readmissions may be related to care processes not captured by the metrics collected or related to non-modifiable unrelated to the index hospitalisation such as the socioeconomic and demographic profiles of the hospital’s patient population, the hospital’s resource availability, patient social support, or mental health issues.”

Concluding, Pandey et al comment that there “were concerning racial/ethnic inequalities in MI-ERR-related hospital penalties”. They add: “Our findings raise questions of whether CMS readmission penalties are equitable and justly applied for hospitals with a high prevalence of socially and/or medically complex patients”. “Future studies are needed to determine whether 30-day readmission rates associated with any other meaningful quality measures and the impact of penalties associated with readmission rates on hospital performance and patient outcomes over time,” the authors observe.

James De Lemos

Study author James A de Lemos (Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, USA) told Cardiovascular News: “While the concept of rewarding or penalising hospitals based on the quality of care provided is intuitively very appealing, we must be certain that the rewards and penalties are fairly applied, and that the metrics used are reflective of the quality of care provided by the hospitals and physicians. Our finding suggest that the risk adjusted myocardial infarction readmission metric currently being used by CMS is neither an accurate measure of care quality nor is it being applied fairly—as hospitals with higher proportions of minority patients and those with serious comorbidities are more likely to receive penalties even though process of care and long-term outcomes are not different.”