Income inequality equals more hospital readmissions

Feb 19 2013

By Christopher Walsh, medwireNews Reporter

Patients living in areas of uneven wealth-distribution are at an increased risk for hospital readmission, according to US research findings published in the BMJ.

The researchers estimate that this increased 30-day risk was responsible for an additional 40,000 hospital readmissions after acute myocardial infarction (MI), heart failure (HF), or pneumonia over the 3-year study period, and they equate the excess risk to that from having a major comorbidity.

However, the increased risk did not translate into higher 30-day mortality rates in patients exposed to income inequality, say Peter Lindenauer (Baystate Medical Center, Springfield, Massachusetts, USA) and co-authors.

The retrospective cohort study included Medicare beneficiaries aged 65 years or older, admitted to hospital for acute MI, HF, or pneumonia between 2006 and 2008. The researchers analyzed readmissions and mortality data for approximately 3.1 million and 2.8 million admissions, respectively.

Income inequality was assessed for all US states, which were then categorized into one of four groups according to their degree of inequality across several factors such as family income, percentage of the population living below the poverty line, education, and various hospital characteristics.

In US states categorized as being in the highest quartile of income inequality, patients admitted for acute MI, HF, or pneumonia were at an increased risk for readmission of 1.5%, 1.5%, and 1.4%, respectively, versus patients residing in states in the lowest quartile.

The researchers estimate that the effect of these increased risks contributed to 7153, 17,991, and 14,127 additional readmissions after acute MI, HF, and pneumonia, respectively.

Discussing the possible causes of this association, the authors suggest that uneven distribution in wealth can lead to an erosion in the underlying social fabric within an area. This breakdown may make it more difficult for patients to manage their own care upon discharge, possibly because the usual social networks and support systems are not in place to ensure that they come to follow-up sessions, or adhere to and comply with complex medication regimens and other instructions.

As many of these same factors are also thought to influence survival itself, the authors are unsure why there is disparity between the readmissions and mortality findings, and recommend more-detailed analysis with longer follow-up periods to explore this further.

"One explanation might simply be that over the span of 30 days, readmission is more sensitive to social conditions than is mortality, and that an effect on mortality might have been observed had we extended the period of observation to one year," they conclude.

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