Association between chronic kidney disease, obesity, cardiometabolic risk factors, and severe COVID-19 outcomes.

INTRODUCTION: Chronic kidney disease (CKD) is a risk factor for acquiring severe Coronavirus disease 2019 (COVID-19) but underlying mechanisms are unknown. We aimed to study the risk associated with CKD for severe COVID-19-outcomes in relation to BMI and diabetes, since they are common risk factors both for CKD and severe COVID-19.

METHODS: This nationwide case-control study with data from mandatory national registries included 4684 patients admitted to the intensive care units (ICUs) requiring mechanical ventilation (cases) and 46840 population-based controls matched by age, sex and district of residency. Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for associations between severe COVID -19 and exposures with adjustment for confounders, in subgroups by BMI, and matched by type 2 diabetes.

RESULTS: The median age was 64 years and 27.7% were female. CKD was observed in 5.4% of the cases and 1.5% of the controls whereas 1.9% and 0.3% had end-stage CKD, respectively. CKD was associated with severe COVID-19 (OR 2.20 [95% CI, 1.85-2.62]), continuous renal replacement therapy at ICU (OR 7.36 [95% CI 5.39-10.05]), and death any time after ICU admission (OR 2.51 [95% CI 1.96-3.22]). The risk associated with CKD for severe COVID-19 did not differ significantly by weight but was higher in non-diabetics (OR, 2.76 [95% CI 2.15-3.55]) than in diabetics (OR, 1.88 [95% CI 1.37-2.59]).

CONCLUSION: CKD, especially end-stage CKD, is an important risk factor for severe COVID-19 and death after ICU-admission also in patients with normal BMI and without type 2 diabetes.