ABSTRACT
BACKGROUND AND AIMS The incidence of acute renal failure (ARF) is frequent and has an implication in the morbidity and mortality of SARS-CoV-2 infection. METHOD A retrospective descriptive study of patients admitted for SARS-CoV-2 infection during the first (G1) and second (G2) waves who presented with ARF. They correspond to the period from March to May 2020 (G1) and from August to December 2020 (G2). We compare populations, outcomes and treatments. RESULTS A total of 73 patients in the first wave (G1), with a cumulative incidence (CI) of 28.3% (G1), compared with 58 patients in the second wave (G2), with a CI of 8% (G2). The mean age was higher in G2 [65.8 ± 15 years (G1);75.3 ± 14 (G2);P <.05], with no difference regarding sex [63% (G1);54% (G2)]. In G2, there was a higher proportion of patients with cardiovascular disease [23% (G1);57% (G2)], hypertension [56% (G1);83% (G2)]. The baseline glomerular filtration rate (GFR) being similar for both groups (CKD EPI: 69 mL/min/1.73² (G1);P = .27). In the first wave, the mean days from admission to ARF was 3.1 days ± 4.2, and 42% of the patients were diagnosed at admission (31 patients). In the second, it was 2.9 days ± 5.7, of which 60% at admission (35 patients). The most prevalent cause was prerenal in both. Higher proportion in G1 of KDIGO stage 3 (G1: 30% versus G2: 17%) and renal replacement therapy (RRT) (G1: 9 versusG2: 2 patients). Only 3 patients remained in RRT in G1 and 1 patient in G2. In G1, 64% recovered their GFR [mean time (MT): 7.5 ± 8 days], and the percentage of deaths was 34%. In G2, 72% recovered GFR (MT: 16 ± 25 days), and 19% of patients died. CONCLUSION Despite a lower age and comorbidity of the first wave patients, the severity and lethality was higher. There were no differences in the proportion of patients who recovered their baseline renal function, although the recovery time was longer in the second wave.Table 1.Characteristics of kidney failure and treatmentsGroup 1Group 2Baseline CKD G1-240 (61%)36 (63%)P = .245 G316 (26%)18 (32%) G4-59 (14%)3 (5%)ARF severity (KDIGO) KDIGO 1 and 251 (70%)48 (83%)P = 0.08 KDIGO 322 (30%)10 (17%)Cause of ARF Prerenal38 (52%)39 (67%)P = 0.121 Sepsis25 (25%) 11 (19%) Obstructive2 (3%)4 (7%) Others8 (11%)4 (7%) Haematuria8 (11%)16 (27%)P = 0.74 ICU18 (25%)3 (5%)P = 0.03 OTI16 (22%)3 (5%)P = 0.007 RRT9 (12%)2 (3%)P = 0.069 ARF recovery time7.5 ± 816 ± 25P = 0.04 Total Patients7358 Group 1: ARF patients on first wave of SARS CoV2. Group 2: ARF patients on the second wave of SARS CoV2. Baseline CKD, baseline chronic kidney disease;ICU, intensive care unit;OTI, orotracheal intubation;and RRT, renal replacement therapy. ARF recovery time: days from renal failure to recovery of baseline renal function.