Socioeconomic Status and Hospital Readmissions

CMS’ hospital readmission penalties program has been under fire for a number of reasons, one of which is that it is more likely to penalize hospitals who care for large numbers of poorer, disadvantaged patients, which may lead to fewer financial resources being available to provide care to these patients.  The implication is that these patients may be more likely to be readmitted for reasons beyond the hospital’s control.  A new study carried by Health Affairs examines socioeconomic status and hospital readmissions.  (HA Article)   The researchers used Medicare data from July 1, 2007 to June 30, 2010 to identify readmissions and other data sources to help identify socioeconomic status.  Socioeconomic status was determined by the zip code of the patient’s address, which isn’t necessarily the best way to do it.  Hospitals were divided into quintiles based on the percent of low socioeconomic status patients they treated.  The looked at the readmission rates for each hospital as CMS currently calculates them, and then they did adjusted analyses incorporating measures of socioeconomic status, both with and without also looking at patient comorbidities.  The end point of the analysis was to then assess how many hospitals that would be penalized under CMS’ current method of calculating expected readmission rates, would not be penalized if the socioeconomic status was included.

There is a significant variation across hospitals in patients socioeconomic status.  Hospitals in the highest socioeconomic status quintile had less than 3% of patients from low socioeconomic status areas, while hospitals in the bottom quintile had more than 90% of their patients living in such geographies.  Patients at the bottom quintile hospitals also had more comorbidities.  The distribution of hospital readmission rate performance was similar for the bottom and top quintile, but was shifted to the right for the bottom quintile, meaning that there were more readmissions across the range of performance.  Having patients with more comorbidities appears to have a much greater impact on readmission rates than does socioeconomic status.   Socioeconomic status alone appears to affect readmission rates by one-tenth of a percent and including socioeconomic status would move about 4% of hospitals of low-socioeconomic status hospitals from being penalized to not being penalized.   The study results can largely be explained by the fact that patients from lower socioeconomic areas have higher comorbidities, which are currently taken into account in the risk model CMS uses for calculating expected readmission rates.  The shortcoming of the study is lumping all patients from a low socioeconomic status area in one bucket.  While comorbidities may be similar, other factors affecting health and self-management of health may not be and really need to be studied at the individual level.  It is these factors that hospitals also are least likely to be able to affect.