INTRODUCTION

Pre-emptive kidney transplantation (KT), or KT before the need for dialysis, is the preferred treatment for end-stage kidney disease (ESKD).1 However, the lack of affordable health insurance in the United States (US) is a known barrier to pre-emptive KT for low-income individuals with ESKD,1 as Medicare benefits are reserved for older adults, the permanently disabled, and those who are dialysis-dependent. Several US states have expanded Medicaid under the Patient Protection and Affordable Care Act (ACA), extending Medicaid coverage to millions of previously uninsured low-income individuals2 including those with non-dialysis-dependent kidney disease.3 The goal of this study was to determine whether Medicaid expansion was associated with changes in Medicaid coverage for pre-emptive living-donor KT (LDKT) and deceased-donor KT (DDKT) in the US.

METHODS

Using national data from the Organ Procurement and Transplantation Network,4 we performed a retrospective study of non-elderly US adults (age 21–64 years) who received pre-emptive KT between January 1, 2010, and December 31, 2017. We excluded multi-organ recipients, those with non-insurance-based payment for KT (n = 31), residents of US territories, and those with missing data on state of residence. Our primary exposure was full implementation of Medicaid expansion under the ACA to include all non-elderly adults at or below 138% of the federal poverty level. Consistent with our prior approach,4 we standardized Medicaid expansion implementation dates for each state that expanded Medicaid during the study period (n = 31 and the District of Columbia),2 and we included January 1, 2014, as the full implementation date for states that had earlier partial expansions of Medicaid.4 We compared the pre- and post-implementation periods in Medicaid expansion states to the periods before and after January 1, 2014, in non-expansion states (n = 19)2 with respect to the following: (1) the proportion of DDKTs that were Medicaid-covered and (2) the proportion of LDKTs that were Medicaid-covered using chi-square tests.

We also compared national trends in Medicaid-covered pre-emptive DDKT and LDKT, respectively, between expansion and non-expansion states by estimating an age, race, and sex-adjusted logistic regression model of pre-emptive KT insurance types (Medicaid/other) within each quarter (3-month period) of our study period. The Drexel University institutional review board approved the study. Analyses were performed using Stata14 (College Station, TX).

RESULTS

Among 15,775 non-elderly pre-emptive KT recipients, the median age was 51 years (interquartile range 42–58 years), 56% were male, and 71% were white. After Medicaid expansion, Medicaid-covered pre-emptive KT recipients from expansion states were more likely to be minorities and to be employed than those from non-expansion states (Table 1). From the pre- to post-expansion periods, the total number of pre-emptive KTs with Medicaid coverage increased relatively by 37% in non-expansion states and by 66% in expansion states. The proportion of pre-emptive DDKTs with Medicaid coverage increased by 0.8 percentage points within non-expansion states (4.6 to 5.4%, p = 0.41) and by 3.8 percentage points in expansion states (7.3% vs 11.1%, p < 0.001). LDKT with Medicaid coverage increased by 0.7 percentage points in non-expansion states (1.7 to 2.4%, p = 0.12) and by 2.2 percentage points in expansion states (3.4 to 5.6%, p < 0.001). In the adjusted quarterly trend analysis of insurance coverage for pre-emptive DDKT and LDKT, respectively (Fig. 1), increases in Medicaid-covered recipients were observable within three quarters of the expansion date in expansion states.

Table 1 Characteristics of Medicaid-Covered Pre-emptive Transplant Recipients in Non-Expansion and Expansion States, Pre- and Post-Medicaid Expansion
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Figure 1
figure 1

Adjusted proportion of non-elderly pre-emptive kidney transplants with Medicaid coverage, with 95% confidence intervals. This figure displays results from an age, race, and sex-adjusted logistic regression model for pre-emptive kidney transplant recipient insurance type (Medicaid/other), comparing 19 non-expansion states to 31 expansion states (and the District of Columbia) for (panel a) living-donor pre-emptive kidney transplants and (panel b) deceased-donor pre-emptive kidney transplants. To account for different calendar dates of Medicaid expansion, results are presented as the number of quarters before and after a standardized Medicaid expansion date, where the date of Medicaid expansion is set to equal zero. The point estimate for each quarter indicates the adjusted proportion of all pre-emptive transplants in that quarter that was Medicaid-covered. The solid line indicates the calendar date of Medicaid expansion for expansion states, and January 1, 2014 for non-expansion states. Blue squares represent proportions of Medicaid-covered pre-emptive transplants in expansion states, with 95% confidence intervals. Red circles represent proportions of Medicaid-covered pre-emptive transplants in non-expansion states, with 95% confidence intervals.

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DISCUSSION

In this study, we found evidence that Medicaid expansion was associated with increases in the proportions of pre-emptive LDKTs and DDKTs, respectively, that were Medicaid-covered. These findings extend our prior work showing that Medicaid expansion was associated with a 59% relative increase in Medicaid-covered pre-emptive KT wait-listings.4 Pre-emptive KT allows individuals with ESKD to avoid the morbidity and mortality associated with dialysis. However, KT is largely restricted to those with health insurance, a known contributor to socioeconomic disparities in rates of pre-emptive KT in the US.1, 5 Given the ongoing coverage gap in states that did not expand Medicaid, the lack of affordable health insurance persists as a substantial barrier to pre-emptive KT for low-income individuals in the US with ESKD.4, 6 An important limitation of our study is that the total population of low-income individuals in the US who may be eligible for pre-emptive KT is unknown. In summary, these results suggest that Medicaid expansion has enabled more low-income US individuals with chronic kidney disease to receive KT before requiring dialysis.