Quantifying income-related inequality in healthcare delivery in the United States

Med Care. 2004 Jan;42(1):38-47. doi: 10.1097/01.mlr.0000103526.13935.b5.


Background: Numerous studies have found that high-income Americans use more medical care than their low-income counterparts, irrespective of medical "need." The methods employed in these studies, however, make it difficult to evaluate differences in the degree of income-related inequality in utilization across population subgroups. In this study, we derive a summary index to quantify income-related inequality in need-adjusted medical care expenditures and report values of the index for adults and children in the United States.

Methods: We used the summary index of income-related inequality in expenditures developed by Wagstaff et al. 1 The source of data for the study was the Household Component of the 1996-1998 Medical Expenditure Panel Survey, which contains person-level data on medical care expenditures, demographic characteristics, household income, and a wide array of health status measures. We used multivariate regression analysis to predict need-adjusted annual medical care expenditures per person by income level and used the predictions to calculate the indices of inequality. Separate indices were calculated for all adults, working-age adults, seniors, and children ages 5 to 17.

Results: For all age groups, predicted expenditures per person, adjusted for medical need, generally increased as income rose. The index of inequality for all adults was +0.087 (95% confidence interval, +0.035, +0.139); for working-age adults, +0.099 (+0.046, +0.152); for seniors, +0.147 (+0.059, +0.235); and for children, +0.067 (+0.006, +0.128).

Conclusions: There exists income-related inequality in medical care expenditures in the United States, and it favors the wealthy. The inequality is highest among seniors despite Medicare, intermediate among working-age adults, and lowest among children.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Aged
  • Child
  • Child, Preschool
  • Female
  • Health Expenditures / statistics & numerical data*
  • Health Services Accessibility / economics*
  • Health Services Research
  • Health Status Indicators*
  • Humans
  • Income / statistics & numerical data*
  • Male
  • Middle Aged
  • Poverty / statistics & numerical data
  • Socioeconomic Factors
  • United States / epidemiology