SARS-CoV-2 PCR cycle threshold value at admission might not be a good predictor of in-hospital COVID-19-associated AKI

Acute kidney injury (AKI) is a prevalent complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and a predictor of disease severity and mortality; furthermore, a prompt diagnosis and treatment of this complication may enhance COVID-19 prognosis. Therefore, we aim to investigate potential risk factors for SARS-CoV-2-associated AKI, including SARS-CoV-2 PCR cycle threshold value (CT value), which correlation with AKI is conflicting.

This case-control study included 110 hospitalized patients with SARS-CoV-2-associated AKI as cases and 110 random SARS-CoV-2 hospitalized patients as controls. Reverse transcription real-time PCR of admission nasopharyngeal swabs evaluated E gene cycle thresholds. Additional clinical and paraclinical information extracted from medical records. The patient's status at discharge, and 14 and 30 days after discharge. Therefore, after adjusting for age and gender, the correlation between variables was assessed.

SARS-CoV-2 AKI is significantly associated with age above 60, hypertension, diabetes mellitus, ischemic heart disease, and underlying kidney diseases. Abnormal admission hemoglobin or alkaline phosphatase, proteinuria or hematuria in urine sediment, and abnormal creatinine during hospitalization were the paraclinical features correlated to SARS-CoV-2 AKI. AKI group demonstrated greater in-hospital, 14- and 30-day mortality. Nevertheless, this study did not evidence a correlation between the admission CT value and mortality or AKI.

Admission CT values provide limited information regarding the dynamic viral load and varying hospitalization time points; thus, they may not be reliable for predicting the prognosis and complications of COVID-19 in all populations. Further studies with serial CT measurements or symptom onset time adjustment are recommended.