CKD and Rapid Kidney Function Decline During the COVID-19 Pandemic.

Rationale & Objective: The direct and indirect effects of the coronavirus disease 2019 (COVID-19) pandemic on kidney function in the chronic kidney disease (CKD) population are not well understood.

Study Design: Cohort study.

Setting & Participants: Retrospective study of kidney function trajectories using deidentified administrative claims and laboratory data for Medicare Advantage and commercially insured enrollees with CKD stages G3-4 between 2018 and 2021.

Predictors: COVID-19 infection.

Outcome: Rapid kidney function decline defined as annual estimated glomerular filtration rate (eGFR) decline of ≥40%.

Analytical Approach: Propensity score matching was used to identify individuals without COVID-19 infection matched 1:1 to a COVID-19 infected cohort and indexed on the date of diagnosing COVID-19 infection, age, sex, race or ethnicity, and Charlson comorbidity index score. Outpatient kidney function was compared during the prepandemic period (January 1, 2018, to February 29, 2020) with the pandemic period (March 1, 2020, to August 31, 2021). Two creatinine measurements, after the infection date and ≥60 days apart, were required to reduce correlation with acute infection.

Results: Of 97,203 enrollees with CKD G3-4, 9% experienced a COVID-19 infection. Characteristics of 8,901 propensity matched enrollees include mean age 74 years, 58% women, 67% White, and 63% CKD G3a, 28% CKD G3b, and 9% CKD G4. Median overall annual eGFR change was -2.65 ml/min/1.73m, with 76% of the cohort experiencing worsened eGFR in the pandemic period. Rapid kidney function decline was observed in 1.9% and 2.0% of enrollees in the prepandemic and pandemic periods, respectively. Rapid kidney function decline was observed in 2.5% of those with COVID-19 infection and 1.5% of those without COVID-19 infection (  0.05). Factors associated with increased odds of rapid kidney function decline during pandemic included Asian race, higher Charlson comorbidity index, advancing CKD stage, prepandemic rapid kidney function decline, and COVID-19 infection.

Limitations: Retrospective study design with potential bias.

Conclusions: COVID-19 infection increased odds of rapid kidney function decline during the pandemic. The downstream impact of pandemic-related eGFR decline on health outcomes, such as kidney failure or mortality, requires further study.

Plain-language Summary: We used a cohort of insured individuals with moderate-to-severe chronic kidney disease (CKD) to compare the rates of rapid kidney function decline in prepandemic and pandemic periods and to evaluate the impact of the coronavirus disease 19 (COVID-19) on kidney function decline. We found that overall rates of rapid kidney function decline did not change during the prepandemic and pandemic periods but were significantly higher in both periods among individuals with a COVID-19 infection. As CKD severity increased, rates of both rapid kidney function decline and COVID-19 increased. Advancing CKD, higher comorbid condition, Asian race, prepandemic rapid kidney function decline, and COVID-19 were all associated with higher odds of rapid kidney function decline in the pandemic. These findings suggest close monitoring is warranted for individuals with CKD and COVID-19.