SCHIP and social disparities in access to care. What can we learn about disparities using epidemiologic measures?

It is not clear how disparities in access to care changed after the State Children's Health Insurance Program (SCHIP). The objective of the research was to determine if there was a decrease in disparities in access to care for children across income and race/ethnicity groups after SCHIP. The study used four years of data from the National Health Interview Survey to depict disparities prior to SCHIP (1997-1998) and six years after SCHIP (2004-2005). For the pre-period, the analysis is based on a sample size of 23,937 and 19,330 in the post-period. Access was measured by health insurance coverage and having a usual source of care. Two epidemiologic measures, the Relative Index of Inequality (RII) and the Population Attributable Risk (PAR), were used to measure and quantify the change in disparities. Using the RII, there was a substantial decrease in income disparities in both health insurance coverage (-26.0 %) and having a usual source of care (-15.8%) following SCHIP. There was also a considerable decrease in the PAR for non-Hispanic Black disparities in both access to care indicators (health insurance -5.5%, usual source of care -5.9%). However, among Hispanic children there was no change in health insurance disparities and a slight increase in disparities in having a usual source of care (8.4%). While the introduction of SCHIP coincided with great improvements in access to care, continuing progress in reducing race/ethnic disparities will require continuation of the SCHIP program or similar targeted health coverage programs.