INTRODUCTION

Kidney disease afflicts approximately 10% of the United States (US) population and is its’ ninth leading cause death.1 Though US individuals with kidney disease can receive Medicare if they qualify by age or require maintenance dialysis, younger individuals with earlier-stage disease are not afforded this coverage. Uninsured US individuals with kidney disease are more likely to be low-income and non-white,2 less likely to receive preventative care,2 and more likely to die or become dialysis dependent.3 Since 2010, minorities and low-income US individuals experienced substantial gains in insurance coverage under Patient Protection and Affordable Care Act (ACA) policies, particularly Medicaid expansion.4 The goal of this study was to examine whether similar trends were evident in insurance coverage and disease awareness among non-elderly US individuals with kidney disease.

METHODS

We analyzed eight waves of the National Health and Nutrition Examination Survey ([NHANES] 2001–2016), a nationally representative cross-sectional survey conducted in 2-year cycles.5 Kidney disease was defined as an estimated glomerular filtration rate (eGFR) of < 60 ml/min/1.73m2 using the CKD-EPI or Schwartz equations for participants age > or < 18 years, respectively, or a urine albumin to creatinine ratio ≥ 30 mg/g. We used recommended calibrations and sampling weights.5 Kidney disease awareness was defined as affirmative responses to the survey question: “Have you ever been told you have weak or failing kidneys?”6 available through 2013/2014. Medicare-eligible participants (including age ≥ 65) and pregnant females were excluded, as were other races/ethnicities (due to small sample sizes).

Health insurance coverage was categorized as uninsured, private, or Medicaid/Children’s Health Insurance Program (CHIP); race/ethnicity as non-Hispanic white (NHW), non-Hispanic black (NHB), or Hispanic; and family income as a percentage of the federal poverty level (FPL) as 0–138%, 139–250%, 251–400%, or > 400%. We estimated adjusted insurance coverage prevalence rates using marginal standardization from a multivariable multinomial logistic regression model adjusted for age, sex, income, and an interaction between survey wave and race/ethnicity. We then calculated age-, race/ethnicity-, and sex-adjusted insurance trends among individuals at 0–138% of the FPL. Kidney disease awareness was calculated by wave and by disease severity. Analyses were performed using Stata version 14.1 (StataCorp, College Station, TX). The study was approved by the Drexel University Institutional Review Board.

RESULTS

Participants’ demographics and income were similar across between survey waves (Table 1). Adjusted insurance coverage rates were stable among NHW with kidney disease from 2001 to 2016 (Fig. 1). From 2001/2002 to 2009/2010, adjusted uninsured rates increased by 9.14 percentage-points among NHBs with kidney disease (p = 0.03) and by 7.0 percentage-points among Hispanics with kidney disease (p = 0.48). Adjusted Medicaid/CHIP coverage increased from 2001/2002 to 2009/2010 by 6.6 percentage-points among NHBs (p = 0.01) and decreased by 0.6 percentage-points among Hispanics (p = 0.80). From 2009/2010 to 2015/2016, adjusted uninsured status decreased by 6.4 percentage-points among NHBs (p = 0.12) and increased by 2.3 percentage-points among Hispanics (p = 0.78). Medicaid/CHIP coverage increased from 2009/2010 to 2015/2016 by 13.1 percentage-points among NHBs (p = 0.001) and by 8.9 percentage-points among Hispanics (p = 0.003). Age-, race-, and gender-adjusted Medicaid/CHIP coverage increased by 20.0 percentage-points (p = 0.008) among participants within 0–138% FPL from 2009/2010 to 2015/2016, corresponding with an 9.2 percentage-point decrease in uninsured status (39.3 to 30.1%, p = 0.23).

Table 1 Demographic Characteristics of Non-elderly US Individuals with Kidney Disease Between 2001 and 2016 (n = 4685)
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Figure 1
figure 1

Age-, sex-, and income-adjusted trends in insurance coverage among non-elderly non-Hispanic white (A), non-Hispanic black (B), and Hispanic (C) US individuals with kidney disease, with 95% confidence intervals (n= 4685).

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Overall, kidney disease awareness varied between waves (Table 1). In 2013/2014, 3.3% of respondents reported kidney disease awareness. Stratified by disease severity, among participants with eGFR < 60 ml/min/1.73m2, 6.9% were aware of kidney disease in 2013/2014, whereas 0.9% of participants with eGFR ≥ 60 ml/min/1.73m2 and albuminuria reported kidney disease awareness.

DISCUSSION

In a nationally representative sample of non-elderly US individuals with kidney disease, Medicaid/CHIP coverage increased substantially among US NHBs, Hispanics, and low-income individuals with kidney disease from 2009/2010 to 2015/2016. Nearly one-in-six non-elderly Hispanics and one-in-three non-elderly NHBs with kidney disease were covered by Medicaid/CHIP in 2015/2016. Yet, over 30% of the lowest-income individuals with kidney disease were uninsured in 2015/2016, and kidney disease awareness remained low. Our study has important limitations, including use of a single measure of serum creatinine and albuminuria (misclassification bias), self-reported insurance coverage, and lack of detail on states of residence. Our results suggest that first-line Medicaid providers have an increasing role in identifying US minorities with kidney disease and in improving kidney disease awareness. Studies are needed to determine impacts of policies that restrict Medicaid coverage on US kidney disease outcomes.