Altered kidney function and acute kidney damage markers predict survival outcomes of COVID-19 patients: A prospective pilot study.

Temiz, M. Z.; Hacibey, I.; Yazar, R. O.; Sevdi, M. S.; Kucuk, S. H.; Alkurt, G.; Doganay, L.; Dinler-Doganay, G.; Dincer, M. M.; Yuruk, E.; Erkalp, K.; Muslumanoglu, A. Y.

Background: The central role in the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), called as coronavirus disease 2019 (COVID-19), infection is attributed to angiotensin-converting enzyme 2 (ACE-2). ACE-2 expressing respiratory system involvement is the main clinical manifestation of the infection. However, literature about the association between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and higher ACE-2 expressing kidney is very limited. In this study, we primarily aimed to investigate whether there is a kidney injury during the course of SARS-CoV-2 infection. The predictive value of kidney injury for survival was also determined. Methods: A total of 47 participants who met the inclusion criteria were included in the study. The participants were classified as COVID-19 patients before treatment, COVID-19 patients after treatment, COVID-19 patients under treatment in ICU and controls. The parameters comorbidity, serum creatinine and cystatin C levels, CKD-EPI eGFR levels, KIM-1 and NGAL levels, urine KIM-1/creatinine and NGAL/creatinine ratios were statistically compared between the groups. The associations between covariates including kidney disease indicators and death from COVID-19 were examined using Cox proportional hazard regression analysis. Results: Serum creatinine and cystatin C levels, urine KIM-1/creatinine levels, and CKD-EPI, CKD-EPI cystatin C and CKD-EPI creatinine-cystatin C eGFR levels exhibited significant difference in the groups. The causes of the difference were more altered kidney function and increased acute kidney damage in COVID-19 patients before treatment and under treatment in ICU. Additionally, incidences of comorbidity and proteinuria in the urine analysis were higher in the COVID-19 patients under treatment in ICU group. Urine KIM-1/creatinine ratio and proteinuria were associated with COVID-19 specific death. Conclusions: We found that COVID-19 patients under treatment in ICU exhibited extremely higher levels of serum cystatin C, and urine KIM-1/creatinine and urine NGAL/creatinine ratios. These results clearly described the acute kidney damage by COVID-19 using molecular kidney damage markers for the first time in the literature. Lowered CKD-EPI, CKD-EPI cystatin C and CKD-EPI creatinine-cystatin C eGFR levels were determined in them, as well. Urine KIM-1/creatinine ratio and proteinuria were associated with COVID-19 specific death. In this regard, considering kidney function and kidney damage markers must not be ignored in the COVID-19 patients, and serial monitoring of them should be considered.