Implications of Increased Medicare Advantage Enrollment for Access to Kidney Transplant Waitlisting

Published in the Journal of the American Society of Nephrology. Here is a link to the article.

Regenstrief Institute authors: Adam S. Wilk, PhD, Kelsey Drewry, PhD, MA

As of January 2021, the 21st Century Cures Act expanded Medicare Advantage eligibility to nearly all Medicare beneficiaries with kidney failure. Enrollment in private Medicare Advantage plans has significantly increased since this policy change, particularly among historically underserved populations.¹ Although insurance type and socioeconomic status are well-known factors influencing transplant access,² the effect of rising Medicare Advantage enrollment on waitlisting and transplant access remains unclear.

Compared with traditional Medicare, Medicare Advantage plans can offer added benefits, such as lower cost-sharing and out-of-pocket spending limits, care management, and transportation support—all of which could facilitate access to transplantation. However, Medicare Advantage plans may also limit access to kidney transplantation through restrictive coverage policies, prior authorization requirements, and narrow provider networks that may exclude certain transplant centers and providers.³

Although longitudinal data from after the 21st Century Cures Act are unavailable, evidence from prior years offers insight into the effect of shifting enrollment from traditional Medicare to Medicare Advantage. Among patients aged 65–80 years initiating dialysis between 2015 and 2020, we (1) described trends in initial insurance type and 1-year waitlisting rates overall and by race, ethnicity, and rural residence and (2) estimated the association between Medicare Advantage versus traditional Medicare and the likelihood of 1-year waitlisting. Notably, the Medicare Advantage population in this study includes individuals who developed kidney failure while already covered by Medicare, allowing Medicare Advantage enrollment before the 2021 policy change.

We identified 336,499 patients who initiated dialysis without prior kidney transplant. Medicare Advantage enrollment increased from 33.2% to 47.4% among year-quarter incident patient cohorts during this period, surpassing traditional Medicare by the last quarter of 2020 (Figure 1A). Despite this increase, the 1-year transplant waitlisting rate remained stable at 2.5% for traditional Medicare and 1.9% for Medicare Advantage enrollees (Figure 1B). Subgroup analyses showed an increase in Medicare Advantage enrollment across all race/ethnicity subgroups. Although there were steeper increases in Medicare Advantage enrollment among racially and ethnically minoritized patients (Figure 1C), waitlisting rates remained relatively stable across groups.

Medicare Advantage beneficiaries had a significantly lower unadjusted hazard of 1-year waitlisting than traditional Medicare beneficiaries (hazard ratio, 0.76 and 95% confidence interval, 0.73 to 0.80; P < 0.001), a difference that persisted after adjustment for demographics, comorbidities, and socioeconomic status (subhazard ratio [sHR], 0.82 [0.78 to 0.87]; P < 0.001). Subgroup analyses showed lower 1-year waitlisting rates among dual-eligible patients (sHR, 0.48 [0.44 to 0.51]; P < 0.001), patients from the most socially vulnerable counties (sHR, 0.69 [0.64 to 0.74]; P < 0.001; quartile 4 versus quartile 1), and those in rural counties (sHR, 0.75 [0.69 to 0.83]; P < 0.001).

We found that patients who begin dialysis under Medicare Advantage have an 18% lower hazard of transplant waitlisting than their traditional Medicare counterparts, a disparity that persists across a period of dramatic Medicare Advantage enrollment growth. This association held after adjusting for patient demographics and health status, notable given that Medicare Advantage enrollment grew disproportionately among patients with kidney failure from historically underserved populations.¹ Although Medicare Advantage plans offer certain advantages, our findings suggest that insurance-related factors may negatively affect transplant access. This may be due to restricted access to in-network transplant centers and specialized care; further research is needed to explore local, geographical, and institutional differences. As Medicare Advantage enrollment continues to grow disproportionately among underserved populations with kidney failure, such Medicare Advantage plan structures could widen inequities in transplant access for these groups.

Policy interventions to address network adequacy and benefit design accounting for moving between traditional Medicare and Medicare Advantage plans⁴ may be needed to ensure equitable access to transplant services. Further research on the experiences of Medicare Advantage enrollees within transplant pathways could clarify the specific barriers they encounter.

Our study’s retrospective, repeated cross-sectional design limits causal inference, and our focus on insurance at dialysis initiation does not account for later insurance changes, which may also influence transplant access.^5,6 By restricting our analysis to patients eligible for Medicare older than 65 years, we were able to observe historical trends in transplant access for Medicare Advantage beneficiaries; however, we could not observe the effect on younger populations. Future studies should explore the causal effects of Medicare Advantage enrollment on transplant access, especially for younger patients and those experiencing insurance transitions after dialysis initiation.

This study used data from the United States Renal Data System (USRDS).⁷ The USRDS contains sociodemographic and clinical information on nearly every patient with kidney failure in the United States. The study cohort consisted of all US patients aged 65–80 years when beginning maintenance dialysis between 2015 and 2020 who had not previously undergone a kidney transplant, with follow-up through March 2022.

Our primary exposure was insurance type at dialysis initiation as documented in the USRDS Payer History File. The primary outcome was time to first waitlisting for kidney transplantation at any transplant center. This outcome was modeled using a subdistribution hazard model with death as a competing risk, adjusting for demographics, dual eligibility, clinical comorbidities, and socioeconomic factors from CMS-2728 forms. Time to waitlisting was censored 1 year after dialysis initiation. Complete case analysis was used; missingness was <2%. Analyses were conducted using SAS 9.3 (Cary, NC).

Authors: 

Joel T Adler ¹, Arnold E Kuk ², Kelsey M Drewry ^3 4, Kevin H Nguyen ⁵, Adam S Wilk ^3 4

Affiliations: 

¹Division of Transplantation, Department of Surgery and Perioperative Care, Dell Medical School at the University of Texas at Austin, Austin, Texas.

²Biomedical Data Sciences Hub, Dell Medical School at the University of Texas at Austin, Austin, Texas.

³Division of Transplantation, Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana.

⁴Regenstrief Institute, Indianapolis, Indiana.

⁵Department of Health Law, Policy, and Management, Boston University School of Public Health, Boston, Massachusetts.