The Affordable Care Act, Medicaid Expansion, and Disparities in Kidney Disease

Introduction

ESRD is a common and lethal condition, and its burden disproportionately falls on the nation’s most disadvantaged communities. Approximately 468,000 Americans regularly receive dialysis (1). Age-adjusted mortality rates are six to eight times higher for those with ESRD compared with the general population (1). The incidence of kidney failure is 3.5 times higher for blacks and 1.5 times greater for Hispanics than for whites (1). Among persons starting dialysis, living in a low-income or racially segregated area predicts worse outcomes (2). Reducing disparities related to kidney disease is an urgent public health priority.

The Role of Health Insurance in Advanced Kidney Disease

Health insurance expansion has been central to improving survival and reducing disparities for persons with ESRD. In 1973, the federal Medicare program extended coverage to the vast majority of persons requiring dialysis. As noted by Eggers, “[p]erhaps no other Federal Government program can lay claim to have saved as many lives as the Medicare [ESRD] program” (3). Before 1973, dialysis was provided to few patients given its high costs and limited availability. Hospitals with dialysis machines often appointed special committees to decide which patients would be offered dialysis, effectively consigning those who were not selected to death. In 1967, one quarter of patients on dialysis were women, and <10% were black. Within 5 years of Medicare expansion, blacks and women represented 35% and 50% of the dialysis population, respectively (3).

Although Medicare has been instrumental in promoting access to life-sustaining dialysis, it does not cover many persons with less advanced stages of CKD, and Medicare coverage for ESRD does not typically begin until the fourth month of dialysis (4). Emerging evidence indicates that racial and socioeconomic gaps related to kidney disease may partially arise from inadequate access to care and lack of health insurance coverage before and immediately after the onset of ESRD. Three lines of research support this assertion. First, the transition to dialysis is associated with high mortality and other adverse events, in part because many patients with incident ESRD are inadequately prepared for dialysis and lack effective predialysis nephrology care. One third of incident patients never receive care from a nephrologist, just 30% received at least 12 months of predialysis nephrology care, and 80% initiate dialysis with a high-risk central venous catheter (1). Among uninsured patients, just 10% receive 12 or more months of predialysis nephrology care, and only 8% have a fistula before dialysis (5). Among patients with ESRD with Medicaid or those who are uninsured, living in a state with more generous Medicaid eligibility is associated with higher rates of placement of permanent vascular access and early transplantation (5).

Second, diabetes and hypertension account for 72% of all incident patients with ESRD (1). Control of BP and glucose through appropriate medication management and tailored lifestyle recommendations can prevent or delay the onset of ESRD. However, among the uninsured, control of glucose and BP is suboptimal, and antihypertensive medications are underused (6). Increased insurance coverage may lead to better recognition and treatment of diabetes and hypertension, although evidence on whether health insurance coverage improves outcomes for these conditions is mixed (7,8).

Third, disparities in treatment and outcomes among patients with kidney disease are attenuated among populations with uniform health insurance coverage. For instance, women and minorities with CKD have lower use of cardiovascular procedures before initiating dialysis, a period when patients either lack insurance coverage or have benefits of varying generosity. However, the onset of ESRD and transition to Medicare coverage reduce these racial and sex gaps (2). Racial and ethnic disparities in diabetes-related complications (including kidney failure) and cardiovascular events are absent or even reversed among persons with uniform coverage in the Veterans Affairs health care system, Department of Defense, and Kaiser Permanente (2).

A conceptual framework adapted from the Institute of Medicine’s panel on the consequences of uninsurance and the Aday–Anderson model of health care use can illustrate the relationship between insurance, access to care, and outcomes (6). Under this framework, insurance is a key enabling factor that promotes the use of potentially beneficial health services (e.g., treatment of diabetes/hypertension and predialysis nephrology care), which in turn, can reduce the likelihood of adverse health outcomes (e.g., kidney failure, hospitalization, and mortality). Other factors that influence access to care include predisposing factors that encompass the sociocultural characteristics of individuals (such as age, race/ethnicity, education, and health-related beliefs), community-related factors, and need. This model elucidates potential pathways to understand how health insurance expansion can produce improvements in health.

The Affordable Care Act and Disparities in Advanced Kidney Disease

The Affordable Care Act (ACA) is the largest expansion of health insurance coverage since the creation of Medicare and Medicaid in 1965. The ACA expanded Medicaid coverage to all qualifying legal residents with income up to 138% of the federal poverty level (FPL). For persons not eligible for Medicaid, the ACA provided federal subsidies for persons with income between 100% and 400% of the FPL to purchase private insurance coverage in regulated state-based exchanges (7). Since 1965, Medicaid has been the nation’s primary health insurer for the poor, but traditionally, it has only covered low-income adults in designated categories of eligibility: pregnant women, parents of dependent children, persons with a disability, and the elderly.

Although the ACA’s architects intended for all states to expand Medicaid, the US Supreme Court in 2012 ruled that the ACA’s Medicaid expansions were unconstitutionally coercive. This judgment ceded the decision of whether to expand Medicaid to each state. Currently, 31 states and Washington, DC have expanded Medicaid, whereas 19 states have not proceeded with expansion—although Maine’s voters recently approved a referendum to expand as of November 2017 (7). In nonexpansion states, many low-income adults fall into an unintended coverage gap, because they are both ineligible for Medicaid and also, do not have sufficient income to qualify for subsidies. Consequently, although the rate of uninsurance in the United States has fallen to a historic low, coverage gains have lagged in nonexpansion states.

One commonly cited rationale for some states’ lack of participation in the expansion is uncertainty about whether Medicaid coverage improves health and quality of care. Some observers have declared on the basis of cross-sectional evidence that having Medicaid is no better than being uninsured (8). However, a robust and growing body of rigorous randomized and quasiexperimental studies suggests that Medicaid coverage is associated with substantial gains in access to care, use of effective health services, self-rated health, and some health outcomes (8).

Perhaps the most influential such study is the Oregon Health Insurance Experiment, a randomized trial of Medicaid coverage (9). The study found that gaining Medicaid led to a 25% increase in the likelihood of reporting “good, very good or excellent health” and a 30% reduction in screening positive for depression as well as nearly eliminating catastrophic out-of-pocket expenses. Although Medicaid increased the use of antihypertensive, lipid-lowering, and glycemic medications, it did not produce statistically significant improvements in BP, cholesterol, and diabetes control. However, the study was limited largely to adults residing in Portland, it followed patients for a median of 18 months, and it was arguably underpowered to detect clinically significant changes in some physical health outcomes. In contrast, a population-based study of three states that expanded Medicaid coverage between 2000 and 2005 found a significant 6% reduction in mortality after expansions, particularly for minorities and those in low-income areas, compared with neighboring nonexpansion states (10). The ACA’s Medicaid expansions also produced gains in BP control for patients in community health centers (7). Post-ACA studies of the CKD population are lacking; however, before the ACA, higher rates of Medicaid coverage in a state were associated with a lower incidence of kidney failure (4).

More broadly, the extent to which insurance improves health likely depends on the population covered, the outcomes considered, and the type of insurance. For instance, just 5% of the Oregon participants had a hemoglobin A1c >6.5%, only 15% had elevated BPs, and deaths during the study were infrequent. For this reason, the estimated effects of Medicaid may have been attenuated. In contrast, among the ESRD population, the mean number of comorbid conditions is four, and the risk of death is six- to eightfold higher than that of the general population (1). Therefore, persons with CKD are a population that likely benefits substantially from obtaining health insurance coverage.

Conclusion

The initiation of the 1973 Medicare ESRD program dramatically expanded access to dialysis and improved survival for patients with ESRD, but it did not include many low-income persons with earlier stages of kidney disease and did not provide coverage during the critical transition period of dialysis initiation. Some four decades later, the ACA’s Medicaid expansions hold great potential for continued progress toward the goal of improving access and outcomes for socioeconomically vulnerable persons with CKD. However, these potential beneficial effects may not be realized in the states that declined to expand Medicaid coverage through the ACA. Moving forward, the consequences of the ACA’s Medicaid expansion on quality of care, health outcomes, and disparities in kidney disease remain unknown and should be of vital interest to the nephrology community, researchers, and policymakers.

Disclosures

A.N.T. reports consulting for the Merck Manual.