State medicaid coverage, ESRD incidence, and access to care

Abstract

The proportion of low-income nonelderly adults covered by Medicaid varies widely by state. We sought to determine whether broader state Medicaid coverage, defined as the proportion of each state's low-income nonelderly adult population covered by Medicaid, associates with lower state-level incidence of ESRD and greater access to care. The main outcomes were incidence of ESRD and five indicators of access to care. We identified 408,535 adults aged 20-64 years, who developed ESRD between January 1, 2001, and December 31, 2008. Medicaid coverage among low-income nonelderly adults ranged from 12.2% to 66.0% (median 32.5%). For each additional 10% of the low-income nonelderly population covered by Medicaid, there was a 1.8% (95% confidence interval, 1.0% to 2.6%) decrease in ESRD incidence. Among nonelderly adults with ESRD, gaps in access to care between those with private insurance and those with Medicaid were narrower in states with broader coverage. For a 50-year-old white woman, the access gap to the kidney transplant waiting list between Medicaid and private insurance decreased by 7.7 percentage points in high (>45%) versus low (<25%) Medicaid coverage states. Similarly, the access gap to transplantation decreased by 4.0 percentage points and the access gap to peritoneal dialysis decreased by 3.8 percentage points in high Medicaid coverage states. In conclusion, states with broader Medicaid coverage had a lower incidence of ESRD and smaller insurance-related access gaps.

Figure 1.

Rates of access to care among privately insured, Medicaid, and uninsured nonelderly adults between 2001 and 2008. AVF, arteriovenous fistula.

Figure 2.

Adjusted odds ratios for indicators of access to care among Medicaid and uninsured nonelderly adults (referent group is privately insured) at varying levels of state Medicaid coverage. Models are adjusted for age, sex, race, body mass index, hypertension, diabetes, heart failure, ischemic heart disease, peripheral vascular disease, cerebrovascular disease, chronic lung disease, cancer, tobacco use, alcohol dependence, drug dependence, and inability to ambulate, in addition to fixed effects for calendar year and state. Note: P value for interaction of state Medicaid coverage×Medicaid insurance<0.01 for all outcomes except early nephrology care (P=0.2) and permanent vascular access (P=0.5). P value for interaction of state Medicaid coverage×uninsured<0.01 for all outcomes except nephrology care (P=0.9) and waitlisting within 1 year of ESRD (P=0.5).

Figure 3.

Difference in access to care, or access gap, between private insurance and Medicaid or uninsured in three states with low, intermediate, and high rates of Medicaid coverage. Access gaps are based on predicted probabilities of access to care for a 50-year-old hypertensive white woman with ESRD in 2005. The average levels of Medicaid coverage for high, medium, and low coverage states are 58.6%, 31.3%, and 18.7%, respectively. WL, waitlist within 1 year of ESRD; Tx, transplant within 1 year of ESRD; PD, peritoneal dialysis; Neph, nephrology care for 12 months before ESRD; AVFG, placement of arteriovenous fistula or graft before ESRD.