ABSTRACT
Background: Recent research suggests that COVID-19 is associated with acute kidney dysfunction. Effect of COVID-19 infection on downstream kidney function is unknown. We investigated this using the BC Interdisciplinary COVID-19 Care Network data. Method(s): This retrospective cohort study analyzed a 2,212 COVID-19 patient cohort, aged >=18 years, referred to the Post COVID Recovery Clinic (PCRC) in BC, Canada between July 9, 2020 & April 21, 2022. COVID-19 diagnosis date was the index date. Patients with history of kidney transplantation or dialysis before index date were excluded. Patients who deceased within 3 months of cohort entry were excluded. eGFR values were retrieved from the Provincial Laboratory Information System. We examined change in eGFR at 3-, 6-, 12-months after COVID-19 infection among the same study individuals using linear mixed model. Subgroup analysis included comparison between hospitalized vs. non-hospitalized, & diabetics vs. non-diabetics. Result(s): Analytic cohort included 457 patients (median age 59 years, 50% male) for whom eGFR was recorded at 3-, 6-, 12-months from index date. Prevalence of reduced eGFR (<=59ml/min/1.73m2) was 16%, 16%, 17% at 3-, 6-and 12-months post-index date, respectively. Median (IQR) eGFR at baseline was 90 (73, 102) that was reduced to 85 (70, 101) at 6-months & remained stable or <previous value at 12 months postindex date, 86 (69, 101). Results from linear mixed model indicated a 0.23 ml/min decrease in eGFR in each month after COVID-19 infection (intercept 85.51, slope -0.23, p-value=0.0003). In subgroup analyses, similar trends of decreasing eGFR over time were observed among diabetic (n=188, intercept 83.08, slope -0.42, p-value=0.0001) & nondiabetic patients (n=269, intercept 87.33, slope -0.12, p-value=0.13). Interestingly, eGFR appeared to improve over time in non-hospitalized patients (n=133, intercept 88.34, slope 0.24, p-value=0.03) compared to a decreasing trend among hospitalized patients (n=324, intercept 83.94, slope -0.41, p-value=<0.001). Conclusion(s): One in 6 COVID-19 patients who were referred to PCRC had reduced eGFR. COVID-19 was associated with a statistically significant decrease in eGFR, particularly in diabetic & hospitalized patients that warrants ongoing monitoring following COVID-19 infection.
ABSTRACT
Background: Recent research suggests that COVID-19 infection is associated with acute kidney injury (AKI). Together the inflammation caused by the virus in the kidneys and the episodes of AKIs are risk factors for progression of kidney diseases. We investigated the risk of progression to kidney failure among chronic kidney disease (CKD) patients from BC, Canada who were infected with COVID-19. Method(s): In this retrospective cohort study, we analyzed a cohort of 22,188 nondialysis CKD patients aged >=18 years, with no prior history of ESKD and COVID-19 infection before the cohort entry date between January 27, 2020 & December 15, 2021. The cohort was derived from Patient Records and Outcome Management Information System (PROMIS), a population based integrated registry database for CKD patients under the nephrologist care in BC. Incident COVID-19 cases were iteratively matched without replacement to non-COVID-19 controls (1:3 ratio) based on age, sex, region of residency, diabetes status, eGFR and urine ACR, CKD vintage and COVID-19 vaccination status as of COVID-19 diagnosis date. The primary outcome was a composite of initiation of maintenance dialysis defined by dialysis performed for >=4 weeks, a sustained decline in eGFR defined by >=40% decline from baseline that sustained over >=4 weeks or incident kidney transplantation. Estimated HR and 95% CI using Fine and Gray subdistribution hazard model to account for death as a competing risk. Result(s): The analytic data included 1,708 patients, 475 (28%) COVID-19 cases and 1,233 (72%) non-COVID-19 controls. Median age was 71 years, 53% was male. Median follow-up was 8.3 months, 70 (4.10%) patients progressed to kidney failure. Among the non-dialysis CKD patients, the risk of developing kidney failure in COVID-19 infected cases was 24% higher compared to matched, non-COVID-19 infected controls. The HR (95% CI) was 1.24 (0.75, 2.06) (p-value: 0.39). Conclusion(s): COVID-19 infection in non-dialysis CKD patients appeared to be associated with higher risk of progression to kidney failure. Although not statistically significant, the substantial increase in risk estimate warrants close monitoring of kidney function among CKD patients after COVID-19 infection.