Social Determinants of Health Impact Hospital Readmission Rates

March 20, 2019 - New research in Health Services Research shows social determinants of health are linked to hospital readmission rates, and accounting for disability, housing instability, and other social risk factors in value-based purchasing models can help level the playing field for safety-net hospitals.

Researchers found that hospitals that serve the most vulnerable patients would see a 21.8 percent reduction in penalties under Medicare’s Hospital Readmissions Reduction Program (HRRP) if CMS adjusted hospital readmission rates for social determinants of health on the patient level.

The reduced penalty rate would translate to about $17 million for the safety-net hospitals participating in the Medicare program that penalizes hospitals that have higher-than-expected readmission rates.

“HRRP penalties cost safety net hospitals millions of dollars each year, but aren't a fair reflection of their performance,” Karen Joynt Maddox, MD, MPH, the study's lead author and Assistant Professor of Medicine in the Cardiovascular Division at Washington University's School of Medicine, stated in a press release. “Adding social risk factors to risk adjustment would be a significant step towards a more equitable program.”

The retrospective study of nearly 3 million Medicare fee-for-service patients hospitalized for three of the conditions in HRRP from 2012 to 2015 revealed a strong link between hospital readmission rates and social determinants of health that can be found through claims.

Researchers found significantly higher raw readmission rates for individuals with dual status, disability, housing instability, and neighborhood disadvantage. For example, dually enrolled acute myocardial infarction (AMI) patients had a raw readmission rate of nearly 19 percent, and AMI patients with disabilities had a rate of 18.1 percent.

In addition, AMI patients residing in highly disadvantaged neighborhoods or discharged from hospitals caring for more patients from highly disadvantaged neighbors were also more likely to be readmitted.

Researchers observed similar trends for pneumonia and chronic heart failure, the other two conditions used in HRRP.

Safety-net hospitals tend to treat more patients with social determinants of health that result in greater odds of readmission, the data revealed. Patients at safety-net hospitals were often dually enrolled in Medicaid and originally entitled to Medicare due to disability. They were also less often white and were more likely to have a higher prevalence of housing instability and reside in highly disadvantaged neighborhoods.

The study indicated that safety-net hospital performance in HRRP is skewed by their population’s social determinants of health, and the hospitals are facing financial stresses as a result.

Accounting for social determinants of health in HRRP would make hospital assessments in HRRP valid and support safety-net hospitals, researchers suggested. In fact, the study showed that adjusting for social determinants of health would reduce the financial penalty for at least one-half of the safety-net hospitals in the program.

In contrast, more affluent hospitals would face higher penalties for their adjusted readmission rates. The hospitals treating higher income, more educated patients would see a 22 percent increase, or $15 million, in penalties under HRRP.

Policymakers have been attempting to incorporate social determinants of health adjustment into HRRP. The 21st Century Cures Act mandated CMS to take social risk into account in HRRP by 2019. CMS is now starting to distribute penalties by comparing hospitals to their peers with similar patient populations.

However, hospital readmission rates impact more than just HRRP performance, researchers stated.

Many value-based purchasing models use hospital readmission rates to assess provider performance. Therefore, the non-risk-adjusted readmission rate may be affecting incentive payments, shared savings, and other value-based purchasing mechanism.

“Failing to account for differences in the social complexity of patients hospitals care for has stripped significant resources away from our safety net,” concluded Mat Reidhead, Vice President of Research and Analytics at the Missouri Hospital Association and a study co-author.

“These are resources that could have been directed toward clinical quality improvement or upstream community health interventions. And while the recent intercession of Congress is certainly a step in the right direction, our findings suggest more can be done to ensure equity in the readmissions reduction program.”