ABSTRACT
BACKGROUND AND AIMS: Acute kidney injury (AKI) is a common complication among patients hospitalized with COVID-19. The incidence of AKI is estimated to be around 5%-80%, according to the series, but data on renal function evolution is limited. Our main objective was to describe the incidence of AKI in patients with SARS-CoV-2 infection;secondarily, we analysed the severity of AKI and medium-term renal function evolution in these patients. METHOD: A retrospective observational study that included patients hospitalized a single hospital, diagnosed with SARS-CoV-2 infection, who developed AKI (March- May 2020). We register clinical and demographic characteristics, creatinine upon admission and prior to discharge, as well as creatinine and CKD-EPI glomerular filtration rate (eGFR) after at least 3 months after discharge. CKD was defined according to KDIGO stages based on the eGFR (G3-G5). The KDIGO classification was used to define and classify AKI. Recovery of kidney function was defined as difference in at discharge or post-hospitalization creatinine < 0.3 mg/dL with respect basal creatinine. The clinical follow-up ranged from admission to death or end of study. RESULTS: Of 258 patients hospitalized with SARS-CoV-2 infection, AKI occurred in 73 (28.3%). 63% (n = 46) were men;the mean of age was 69 years (57-76). DRA severity: 35 (48%) KDIGO-1, 15 (21%) KDIGO-2 and 23 (31%) KDIGO-3. The mean stay was associated with the severity of AKI: 7 days (3-11) for KDIGO-1, 11 days for KDIGO-2 (5-22) and 12 days (8-35) for KDIGO-3 (P = .02). The stage of CKD established differences in the severity of AKI: 66.6% (n = 6) of the patients with CKD G4-G5 presented AKI-KDIGO 3 versus only 25.0% (n = 4) in the CKD-G3 patients (P = .02). Admission to the ICU was more frequent in KDIGO 2-3 versus KDIGO-1 [39% (n = 15) versus 9% (n = 3);P < .01]. Of the 48 patients discharged, 30 (62.5%) had recovered their baseline renal function upon discharge. Only 2 are still on RRT after 8 months (2.7% of all patients). Of the 25 patients died (34% of patients with AKI) with a median time of 3 days from DRA diagnosis (1-8). Renal function of 35 patients was monitored, which correspond to 19 (54%) KDIGO- 1, 8 (23%) KDIGO-2, 8 (23%) KDIGO-3 stages. In these patients, analytical control starting 3 months after hospitalization revealed FG 66 (SD 30;56-76) mL/min/1.73 m2. We have not found differences in renal function between pre- and posthospitalization in related test. A total of 77% (n = 37) of discharged patients recovered their baseline renal function in the post-hospitalization control. CONCLUSION: The incidence of AKI in the context of COVID-19 in our series was 28.3%, with an associated mortality of 34.2%. Most of the patients presented with AKI KDIGO 1 (47.9%). The severity of AKI is associated with a longer hospital stay, admission to the ICU and the requirement for RRT. The advanced stages of CKD preadmission showed more severity of AKI. The maintenance in TRS in our series has been 2.7%. Patients who were discharged for recovery/improvement of COVID-19 had normalized kidney function during subsequent follow-up, regardless of the severity of the AKI developed on admission for COVID-19. (Figure Presented).