Patient Socioeconomic Status and Hospital Readmission Rates

Programs that seek to lower hospital admissions rates may also reduce readmissions, even though patients in communities adopting the programs tend to be sicker when hospitalized, according to a recent study in Health Affairs.

The study, by Susannah M. Bernheim, MD, of Yale University, and colleagues, analyzed Medicare data, focusing on communities with hospitals that are major referral centers. The study was undertaken to contribute to the public debate about whether patients’ socioeconomic status should be included in the readmission measures used to determine penalties in Medicare’s Hospital Readmissions Reduction Program (HRRP).

The investigators used current CMS methodology to compare risk-standardized readmission rates for hospitals caring for high and low proportions of patients of low socioeconomic status. They calculated risk-standardized readmission rates after also adjusting for patients’ socioeconomic status. They included admissions for 526,272 acute myocardial infarctions (AMI) to 4432 hospitals; 1,278,296 heart failure admissions to 4733 hospitals; and 1,099,230 pneumonia admissions to 4773 hospitals.

Hospitals deemed to be low socioeconomic status had, on average, more than 90% of their measured patients living in a ZIP code with a median household income of less than $43,710. Those with highest socioeconomic status had, on average, fewer than 1% of measured patients from low-income ZIP codes admitted for AMI and between 2% and 3% admitted for heart failure and pneumonia. Patients at low socioeconomic status hospitals had higher rates of many, but not all, comorbid diseases.

A reduction in hospital admissions was strongly associated with a reduction in 30-day readmissions, a finding that held true despite the fact that the patients who were hospitalized in the communities with the largest reductions in hospital admission rates were sicker upon arrival at the hospital. The analysis found that hospitals caring for large proportions of patients of low socioeconomic status have readmission rates similar to those of other hospitals.

Readmission rates calculated with and without adjusting for patients’ socioeconomic status were highly correlated. Readmission rates of hospitals caring for patients of low socioeconomic status changed by approximately 0.1% with adjustment for patients’ socioeconomic status, and only 3% to 4% fewer such hospitals reached the threshold for payment penalties in Medicare’s HRRP. Thus, adjustment for socioeconomic status did not, overall, change hospital results in meaningful ways.

“We’re showing that communities can do a good job of improving both population health and outcomes after hospitalization,” said study author Kumar Dharmarajan, MD, assistant professor of cardiology at Yale University. Strategies that improve community health overall appear to also improve health after hospital discharge, he said. The results of the study suggest that efforts to improve community health and reduce hospital admissions go together, without negatively affecting readmissions and health outcomes.

The results are reassuring that hospitals with various mixes of patient socioeconomic status can achieve low readmission rates, the authors conclude.

“However, much remains to be learned about strategies for low-socioeconomic-status hospitals and about whether such hospitals are able to improve at the same rate as others,” the authors wrote.