Our study also shows the important role of Cystatin C in the prediction of AKI among patients with COVID-19—AKI vs. non-AKI (SMD = 6.28; 95%CI: 1.11 to 11.44; p = 0.02) Moreover, COVID-19 increases CKD risk in addition to AKI related to it, according to American research that used electronic health data from the Veterans Health Administration to carry out a thorough evaluation long-COVID-19. The gene discussed is CST3; the disease is acute kidney injury.