ACUTE KIDNEY INJURY IN COVID-19 PATIENTS

Acute kidney injury (AKI) often complicates the progression of COVID-19 and increases in-hospital mortality. 
The aim of the study is to analyze AKI frequency, the time of its development and the possibility of using the ratio blood urea nitrogen/blood creatinine (BUN/Cr) as a biomarker for AKI progression in COVID-19 patients. 
Materials and methods. The authors examined 329 patients hospitalized with COVID-19 (157 women (47.7 %) and 172 men (52.3 %), mean age 58.0±14.3 years). The follow-up period was 12 months. COVID-19 was confirmed by a PCR test. AKI frequency, severity and time of development were studied in all patients. Moreover, the authors calculated the ratio blood urea nitrogen/blood creatinine (BUN/Cr, mg/dl:mg/dl). 
Results. AKI was diagnosed in 70 patients (21.3 %), including 12 patients (17.1 %) with an increase in creatinine level after hospitalization (in-hospital AKI) and 58 patients (82.9 %) with a high creatinine level (pre-hospital AKI). AKI stage 1 was observed in 55 patients (78.6 %), stage 2 – in 11 patients (15.7 %), stage 3 – in 4 patients (5.7 %). In-hospital mortality in COVID-19 patients with AKI was 10 %, the relative mortality risk in COVID-19 patients with AKI was 5.3 (95 %, CI 1.7–16.1; p=0.01). In patients hospitalized with AKI, AUB/Cr>20 was observed on hospitalization in 16 patients (27.6 %). In patients with in-hospital AKI, AUB/Cr>20 was detected only in 1 person (8 %). 
Conclusion. One in four patients hospitalized with COVID-19 develop AKI, predominantly stage 1. AKI increases in-hospital mortality. In most patients, AKI develops before hospitalization. In 27.6 % of patients with pre-hospital AKI, AUB/Cr>20 on hospitalization, which indicates the prerenal nature of AKI and the importance of dehydration (hypovolemia) as a risk factor for AKI progression in COVID-19 patients.