Increased vulnerability to Covid-19 in chronic kidney disease.

Background The significance of chronic kidney disease on susceptibility to COVID-19 and subsequent outcomes remains unaddressed. Objective To investigate the association of eGFR on risk of contracting COVID-19 and subsequent adverse outcomes. Methods Rates of hospital-diagnosed COVID-19 were compared across strata of eGFR based on conditional logistic regression using a nested case-control framework with 1:4 matching of patients diagnosed with COVID-19 with controls from the Danish general population on age, gender, diabetes, and hypertension. Risk of subsequent severe COVID-19 or death was assessed in a cohort study with comparisons across strata of eGFR based on adjusted Cox regression models with G-computation of results to determine 60-day risk standardized to the distribution of risk factors in the sample. Results eGFR was inversely associated with rate of hospital-diagnosed COVID-19: eGFR 61-90 ml/min/1.73m2 HR 1.13 (95% CI 1.03 - 1.25), p=0.011; eGFR 46-60ml/min/1.73m2 HR 1.26 (95%CI 1.06 - 1.50), p=0.008; eGFR 31-45ml/min/1.73m2 HR 1.68 (95%CI 1.34 - 2.11), p 90 ml/min/1.73m2 as reference), and renal impairment was associated with progressive increase in standardized 60-day risk of death or severe COVID-19; eGFR >90ml/min/1.73m2 13.9% (95%CI 9.7-15.0); eGFR 90-61ml/min/1.73m2 16.1% (95%CI 14.5-17.7); eGFR 46-60 ml/min/1.73m2 17.8% (95%CI 14.7-21-2); eGFR 31-45 ml/min/1.73m2 22.6% (95%CI 18.2-26-2); and eGFR ≤30 ml/min/1.73m2 23.6% (95%CI 18.1-29.1). Conclusions Renal insufficiency was associated with progressive increase in both rate of hospital-diagnosed COVID-19 and subsequent risk of adverse outcomes. Results underscore a possible vulnerability associated with impaired renal function in relation to COVID-19.