US Renal Data System 2022 Annual Data Report: Epidemiology of Kidney Disease in the United States

The United States Renal Data System 2022 Annual Data Report (ADR) contains data from medical claims through 2020 and for some end-stage renal disease (ESRD)-related metrics through the first half of 2021. As such, this is the first year in which the wide-ranging effects of the coronavirus disease 2019 (COVID-19) pandemic on the chronic kidney disease (CKD) and ESRD populations can be placed into the full context of the years that preceded its onset. Another important aspect of this year’s ADR is a continued focus on racial, ethnic, and socioeconomic disparities in access to health care and outcomes. Unfortunately, these 2 topics intersect in the form of racial and ethnic disparities in vulnerability and susceptibility to COVID-19 that further exposed and exacerbated pre-existing disparities in incidence, prevalence, and care of patients with kidney disease.

Direct and Indirect Effects of COVID-19 on the CKD and ESRD Populations

The devastating effects of the COVID-19 pandemic on the CKD and ESRD populations permeate the 2022 ADR. The 2022 ADR includes data on medical care and outcomes through calendar year 2020 (although some data for the first half of 2021 for the ESRD population are included). Although we presented early views into the impact of the COVID-19 pandemic on the ESRD population in the 2020 ADR and expanded these analyses to include examination of COVID-19 diagnoses and outcomes in the CKD population in the 2021 ADR, the full magnitude of the direct and indirect effects of the pandemic on these populations comes into sharp focus throughout this year’s report.

The direct effects of COVID-19 can be measured by examining patterns of patient testing, hospitalization, and mortality. More than 10% of patients with CKD, 13% of patients with a kidney transplant, and 20% of patients receiving dialysis in January of 2020 were diagnosed with COVID-19 by the end of June 2021, rates that were approximately 50%, 100%, and 200% higher than that of Medicare beneficiaries without CKD, respectively. Although the incidence of COVID-19 testing was higher among individuals with CKD, the incidence of hospitalization after COVID-19 diagnosis among patients with CKD was more than double that of patients without CKD in 2020; patients receiving dialysis consistently had hospitalization rates higher still than those with CKD. Mortality at 14, 30, and 90 days after diagnosis of COVID-19 was more than twice as high among beneficiaries with CKD as among those without. Nearly one-quarter of patients with CKD who were diagnosed with COVID-19 died within 90 days. Mortality after COVID-19 diagnosis was even higher for patients with ESRD, reaching 40.5% for patients receiving dialysis and 44.1% among kidney transplant recipients 90 days after diagnosis.

The ultimate result of the higher incidence of COVID-19 and higher mortality after diagnosis of COVID-19 among patients with CKD and ESRD was the unprecedented shrinking of the prevalence of diagnosed CKD (CKD Volume, Fig 2.1) and ESRD (ESRD Volume, Fig 1.5) in 2020. For example, the absolute increase in mortality in 2020 among patients with CKD was 8.9 deaths per 1,000 person-years, compared with 6.1 per 1,000 person-years among individuals without CKD (Fig 3.2a). By the end of 2020, the population with diagnosed CKD had decreased by 4.3% from 2019. Some of the decline in the CKD population in 2020 may have been an artifact of fewer opportunities to accrue CKD diagnoses given the lower rates of hospitalization that occurred in 2020, combined with a general reduction in overall interaction with the health care system that occurred across the United States. However, this is not true of the ESRD population, whose tracking through EQRS (End Stage Renal Disease Quality Reporting System) and OPTN (Organ Procurement and Transplantation Network) does not rely on diagnosis claims. As a result of fewer patients reaching diagnosed ESRD and the increase in mortality rate among patients with ESRD attributable to the pandemic and its effects, the rate of prevalent ESRD decreased by almost 2% in 2020.

Indirect pandemic effects may have also affected patients with CKD to a greater extent than patients without kidney disease. Rates of emergency department encounters and hospitalizations decreased substantially in 2020 among patients with and without CKD and ESRD. However, the negative consequences of forgoing this medical care may have led to a disproportionate increase in mortality among patients with CKD because of their higher comorbidity burden and higher a priori risk of adverse outcomes. For example, mortality increased more in 2020 among patients with stage 4 and 5 CKD than among patients with stage 3 CKD.

Mortality after COVID-19 was higher among Black and Hispanic Medicare beneficiaries with CKD than among White beneficiaries (Fig 13.5). As a direct result of this higher COVID-19-related mortality and, possibly, more limited access to non-COVID-19-related medical care, mortality increased more among Black than among White beneficiaries with stage 4 and 5 CKD in 2020. This resulted in a reversal of the longstanding observation of lower mortality among Black patients. In other words, whereas Black beneficiaries had lower mortality than White ones in 2019 and prior years, they had higher mortality than their White counterparts in 2020 (Fig 3.2b). Although unadjusted mortality was not higher among Black than among White patients with ESRD, rates of COVID-19 diagnosis were higher (Fig 13.2b). A similar reversal of the Black-White mortality difference occurred in transplant recipients: mortality was higher among White recipients in 2019 but among Black recipients in 2020 (Fig 6.5b). The mortality difference did not reverse among patients treated with dialysis, but it did narrow from 43% higher mortality among White patients in 2019 to only 30% higher mortality in 2020.

Other direct and indirect effects of COVID-19 and the changes in availability and delivery of health care that occurred in 2020 can be seen throughout the ADR and in many metrics typically tracked in the CKD and ESRD populations.

Examples among patients with CKD include:

• Among patients with CKD, there was a particularly steep reduction in the rate of all-cause hospitalization in 2020 (14.9%); this single-year decrease was larger than the cumulative change over the previous 6-year period from 2013 to 2019 (Fig 3.4). Rates of emergency department encounters were also considerably lower in 2020 (Fig 3.15d).

• Although rates of readmission within 30 days of hospital discharge remained stable in 2020 among patients with CKD, the rate of death within 30 days of hospital discharge (without rehospitalization) increased by almost 20% (Figs 3.13 and 3.14d).

• Although the overall rate of hospitalization with acute kidney injury (AKI) decreased in 2020 (likely related to the overall reduction in hospitalization rate; Fig 4.1), AKI events worsened, as indicated by a 16% increase in the need for dialysis among those with AKI (Fig 4.2). This increase occurred after a sustained period of decreasing need for dialysis during hospitalization with AKI.

• Outcomes after AKI requiring dialysis (AKI-D) during a COVID-19 hospitalization in 2020–2021 were substantially worse than outcomes after AKI-D without COVID-19: almost three-quarters (74.1%) of those with COVID-19 and AKI-D died during hospitalization or were discharged to hospice care, compared with 35.2% of those without COVID-19 (Fig 4.4c).

• Inflation-adjusted overall Medicare fee-for-service (FFS) spending for older (≥66 years) beneficiaries with non-dialysis-dependent CKD decreased by almost 3% in 2020, or by ~$2.2B (Fig 6.3). Inpatient spending decreased by 4%, which was a combination of a ~$2.4B decrease in spending on non-COVID-19 hospitalization plus approximately $1.4B in spending for COVID-19 hospitalization (Fig 6.4).

• Hydroxychloroquine and chloroquine use among older Medicare Part D beneficiaries with CKD spiked in March and April 2020 (Fig 7.13), at a time when rates of receipt of many common drugs used to treat hypertension or CKD transiently declined (Fig 7.10). Rates of ivermectin use increased dramatically in November and December of 2020 among older Medicare Part D beneficiaries with CKD (Fig 7.14).

Additional examples of direct or indirect effects of COVID-19 on patients with ESRD are also numerous:

• The percentage of patients with incident ESRD in 2020 starting in-center hemodialysis decreased, and the corresponding percentage starting peritoneal dialysis increased (Fig 1.2).

• The percentage of older Medicare beneficiaries with ESRD and diabetes who received preventive care, including glycated hemoglobin (A1c) testing, lipid testing, and eye examination, decreased in 2020 (Fig 3.15). Only about 25.6% of patients received all 3 of these examinations, compared with 31.4% in 2019.

• The percentage of patients initiating hemodialysis with a catheter increased in 2020 to 71.2%, and the corresponding percentage initiating with an arteriovenous fistula (AVF) decreased to 25% overall (including AVFs that were maturing or were in use, or 14.1% for AVFs used at dialysis initiation; Fig 4.1).

• The number of patients with ESRD newly added to the kidney transplant waitlist in 2020 decreased by 12% (Fig 7.1). There was a corresponding decrease in the total number of patients with ESRD on the waitlist that was particularly pronounced for those listed with active status (Fig 7.2). The percentage of dialysis patients on the kidney transplant waitlist also declined in 2020 (Fig 7.3).

• The rate of receipt of living donor kidney transplants among patients receiving dialysis decreased by 27.3% in 2020 (Fig 7.10a).

• Adjusted 1-year post–kidney transplant patient and allograft survival decreased in 2020 among recipients of living and deceased donor kidney transplants (Figs 7.19a and 7.20a).

• The number of children with incident ESRD decreased in 2020, driven primarily by a reduction in the number who received a preemptive kidney transplant (Figs 8.1 and 8.3b).

• The rates of kidney transplantation among children receiving dialysis decreased by 6% in 2020 (Fig 8.13).

• Total Medicare spending for beneficiaries with ESRD decreased by $2.2B in 2020 (Fig 9.1). Medicare FFS spending for ESRD beneficiaries as a percentage of total FFS spending decreased to 6.1% in 2020 after 10 years at 7.1% to 7.2% (Fig 9.3). The biggest (inflation-adjusted) decrease in FFS spending for ESRD was for outpatient spending (-$1B), and inpatient spending decreased by $0.6B (Fig 9.5).

• Hydroxychloroquine and chloroquine use among Medicare Part D beneficiaries with ESRD spiked in March and April 2020 (Fig 10.13). Rates of ivermectin use increased dramatically in November and December of 2020 among Medicare Part D beneficiaries with ESRD (Fig 10.14).

Racial, Ethnic, and Socioeconomic Disparities

In the 2021 ADR, we did not observe disparities in rates of outpatient nephrology visits or receipt of medications to treat CKD or its complications, including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, oral potassium or phosphorus binders, or sodium-glucose cotransporter-2 inhibitors, by race/ethnicity. Rates of nephrology encounters also differed little by level of neighborhood deprivation. These results suggest that Medicare coverage, including Part D and the Low Income Subsidy, appeared to provide comparable access to care for CKD across race/ethnicity groups and across levels of neighborhood deprivation. We hypothesized that barriers to access to care before Medicare eligibility likely contribute to the higher rates and earlier onset of diabetes and hypertension among Black and Hispanic individuals as well as to the higher risk of subsequent CKD and ESRD. To address this question, this year’s ADR includes data on younger Medicaid beneficiaries aged 18 to 64 years, in which we examined access to medications and nephrology care in these younger patients. We again found little disparity by race/ethnicity or by neighborhood in receipt of medications or nephrology encounters. However, rates of nephrology encounters among younger Medicare beneficiaries were less than half those among older Medicare beneficiaries. Thus, the younger, more heavily Black, Hispanic, and lower-socioeconomic-status Medicaid population appeared to have considerably less access to nephrology care. Medicaid coverage may provide less access to nephrology care than Medicare coverage, or insurance coverage may be insufficient to overcome barriers to accessing care experienced by younger patients with low socioeconomic status, such as transportation or concerns about loss of work income. Furthermore, limitations in access to Medicaid (eg, across U.S. states) likely introduce further disparities that cannot be examined using medical claims, as uninsured patients almost certainly have more limited access to care. Further examination of these issues using more detailed data sources will be critical to developing and implementing strategies to address health care disparities.