MO328: Acute Renal Failure in COVID-19: Aetiology and Renal Evolution. AKI-COVID Registry of the Spanish Society of Nephrology
Authors: Almenara Tejederas Marina , Luisa Serrano Salazar María , Rosa Melero Martin María , Molina-Andújar Alicia , Ramos Terrada Natalia , Poch Lopez de Briñas Esteban , Ángeles Rodríguez-Pérez María , Díaz Mancebo Raquel , Echarri Carrillo Rocío , Portolés-Perez Jose M , José Soler Romero María , Salgueira Lazo Mercedes 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Acute kidney injury (AKI) has been described as a frequent complication in patients with COVID-19. The incidence of AKI is estimated to be around 5%–80% depending on the series; however, data characterizing the type of AKI and the evolution of renal function parameters in the medium-long term are still limited.

METHOD
Based on the initial AKI-COVID Registry, we developed an extended registry where we registered retrospectively new variables that included clinical and demographic characteristics, infection severity parameters and data related to AKI (ethology, KDIGO classification, need of renal replacement therapy, analytic values: baseline creatinine, maximum creatinine during admission, creatinine at discharge or death, creatinine at 1 month after hospitalization and urinary parameters). Recovery of kidney function was defined as difference in at discharge or posthospitalization creatinine &lt; 0.3 mg/dL with respect basal creatinine.

RESULTS
Our analysis included 196 patients: 74% male, mean age 66 + 13 years; 65% hypertensive, 33% diabetic and 22% chronic kidney disease. According to the KDIGO classification: 66% AKI KDIGO3, 17% KDIGO2 and 15% KDIGO1. Creatinine values ​​are summarized in Table 1. We found significant differences in the baseline/high creatinine differential; these differences were lost after hospitalization.
The main types of AKI were prerenal (35%) and acute tubular necrosis secondary to sepsis (ATN) (53%). 89% of patients with ATN presented AKI KDIGO 3, compared with 57% in the prerenal group (P &lt; .001). Patients with prerenal AKI had greater comorbidity. On the other hand, patients with ATN AKI developed more serious COVID-19 infection: higher percentage of severe pneumonia, admission to the intensive care unit and need for orotracheal intubation. The analytical parameters were more extreme in patients with ATN AKI, except for creatinine and urea upon admission, which were higher in the prerenal AKI group.
A total of 89 patients died during the study; 65% of ATN AKI patients versus 31% of prerenal-AKI patients (P &lt; .001). The ATN was a mortality risk factor, whit a hazard ratio 2.74 [95% confidence interval (95% CI )1.29–5.7] (P = .008) compared with the prerenal AKI.

CONCLUSION
AKI in hospitalized patients with COVID19 presented with two different clinical patterns. Prerenal AKI more frequently affected older, more comorbid patients, and with a mild COVID19 infection. The NTA AKI affected younger patients, with criteria of severity of infection and multiplying mortality almost three times. In analytical control 1-month post-hospitalization, most of the patients recovered their kidney function. Although the implications of AKI associated with COVID-19 in the development of chronic kidney disease are still unclear, our data suggest that most patients will recover kidney function in a medium term.