Acute Kidney Injury in Patients with the New Coronavirus Infection

Abstract

Estimations of the frequency of acute kidney injury in SARS-CoV-2 (COVID-19) coronavirus disease are very diverse. The literature data is highly inconsistent and shows AKI ranging from 0.5 to 80%.The objective: to analyze the incidence of renal dysfunction in COVID-19 patients and assess the significance of systemic inflammation for its development.Subjects and methods: The analysis was performed basing on data of 3,806 patients with COVID-19 treated at the Pavlov State Medical University, 395 of them were admitted to the intensive care units (ICU). The criterion for establishing renal dysfunction (RD) is the increase in blood creatinine level above the upper limit of reference values (0.115 mmol/l). Patients with end-stage chronic kidney disease who needed to continue routine long-term dialysis were not included in the study. We analyzed the incidence of renal dysfunction, changes in blood levels of creatinine, urea, and electrolytes during 8 days. In addition, glomerular filtration rate, diuresis volume, levels of hematocrit, hemoglobin, LDH, CRP, ferritin, and procalcitonin were evaluated.Results. The frequency of RD among all patients was 19.0%, among patients in the ICU – 41.0%. In 79% and 81%, respectively, it was detected on the first day of hospitalization. The increase in the number of patients with RD and the aggravation of the existing dysfunction occurred after 6 days. At the initial stage of the disease, the manifestations of RD in most cases were not expressed even in those with an unfavorable course of the disease but the level of creatinine showed a weak but significant (p < 0.5) correlation with changes in CRP (r = 0.110), ferritin (r = 0.137), and procalcitonin (PCT, r = 0.418). The difference in the level of creatinine in patients with PСT level above and below 0.5 ng/ml was observed on the first day only; the value of this parameter returned to normal faster in the subgroup of patients whose procalcitonin level did not exceed 0.5 ng/ml.Conclusion. In case of the signs indicative of RD, it is advisable to distinguish between primary and secondary injury. In the first case, it is primarily due to systemic inflammation, in the second case it is caused by additional impact of other aggressive factors. This will make it possible to clarify the renal and non-renal indications for renal replacement therapy (RRT) in patients with COVID-19, and to evaluate the results adequately since the effectiveness of RRT at different stages of the disease cannot be the same.