Epidemiology and Outcome of Early-Onset Acute Kidney Injury and Recovery in Critically Ill COVID-19 Patients: A Retrospective Analysis

Abstract

Background: The clinical significance of early-onset acute kidney injury (EO-AKI) and recovery in severe COVID-19 intensive care unit (ICU) patients is poorly documented.

Objective: The aim of the study was to assess the epidemiology and outcome of EO-AKI and recovery in ICU patients admitted for SARS-CoV-2 pneumonia.

Design: This was a retrospective single-centre study.

Setting: The study was carried out at the medical ICU of the university hospital of Clermont-Ferrand, France.

Patients: All consecutive adult patients aged ≥18 years admitted between 20 March 2020 and 31 August 2021 for SARS-CoV-2 pneumonia were enrolled. Patients with chronic kidney disease, referred from another ICU, and with an ICU length of stay (LOS) ≤72 h were excluded.

Interventions: EO-AKI was defined on the basis of serum creatinine levels according to the Kidney Disease Improving Global Outcomes criteria, developing ≤7 days. Depending on renal recovery, defined by the normalization of serum creatinine levels, EO-AKI was transient (recovery within 48 h), persistent (recovery between 3 and 7 days) or AKD (no recovery within 7 days after EO-AKI onset).

Measurements: Uni- and multivariate analyses were performed to determine factors associated with EO-AKI and EO-AKI recovery.

Main results: EO-AKI occurred in 84/266 (31.5%) study patients, of whom 42 (50%), 17 (20.2%) and 25 (29.7%) had EO-AKI stages 1, 2 and 3, respectively. EO-AKI was classified as transient, persistent and AKD in 40 (47.6%), 15 (17.8%) and 29 (34.6%) patients, respectively. The 90-day mortality was 87/244 (35.6%) and increased with EO-AKI occurrence and severity: no EO-AKI, 38/168 (22.6%); EO-AKI stage 1, 22/39 (56.4%); stage 2, 9/15 (60%); and stage 3, 18/22 (81.8%) (p < 0.01). The 90-day mortality in patients with transient or persistent AKI and AKD was 20/36 (55.6%), 8/14 (57.1%) and 21/26 (80.8%), respectively (p < 0.01). MAKE-90 occurred in 42.6% of all patients.

Conclusions: In ICU patients admitted for SARS-CoV-2 pneumonia, the development of EO-AKI and time to recovery beyond day 7 of onset were associated with poor outcome.

Keywords: COVID-19; acute kidney injury; intensive care; outcome.

Figure 1

COVID-19 patient flow diagram. ICU: intensive care unit; AKI: acute kidney injury; KDIGO: Kidney Disease Improving Global Outcomes.

Figure 2

Cumulative incidence of early-onset acute kidney injury (EO-AKI) (A) and renal recovery (B) taking into account competing risks of discharge alive and mortality.

Figure 3

Factors associated with occurrence of AKI, multivariate analyses, logistic regression model. Variables with a p-value < 0.1 in the univariate analyses were age, cardiovascular disease, impaired immune system, time from first symptoms to ICU admission, antimicrobial therapy, aminoglycosides, vasopressors, invasive mechanical ventilation, bacteriemia on admission and procalcitonin. Because of correlations, only the following covariates were tested in multivariate analysis: age, cardiovascular disease, impaired immune system, time from first symptoms to ICU admission, aminoglycosides, vasopressors and procalcitonin.

Figure 4

Factors associated with recovery from AKI, multivariate analyses, sub-distribution model. AKI: acute kidney injury; SubHR: sub hazard ratio. Variables with a p-value <0.1 in univariate analyses were age, lopinavir–ritonavir, diuretics, vasopressors and KDIGO stage. These covariates were considered into the final model.