Kidney Replacement Therapy in COVID-19-Related Acute Kidney Injury: the Importance of Timing

The objective of this study was to evaluate two different criteria for deciding when KRT should be initiated in patients with COVID-19-related AKI, as well as to determine the impact of the timing of KRT, as defined by each criterion, on in-hospital mortality among such patients. This was a retrospective study involving 512 adult patients admitted to the ICU. All participants had laboratory-confirmed COVID-19 and a confirmed diagnosis of AKI. The potential predictors were the determination of the timing of KRT based on a temporal criterion (days since hospital admission) and that based on a serum creatinine cutoff criterion. Covariates included age, sex, and the SOFA score, as well as the need for mechanical ventilation and vasopressors. The main outcome measure was in-hospital mortality. We evaluated 512 patients, of whom 69.1% were men. The median age was 64 years. Of the 512 patients, 76.6% required dialysis after admission. The overall in-hospital mortality rate was 72.5%. When the timing of KRT was determined by the temporal criterion, the risk of in-hospital mortality was significantly higher for delayed KRT than for timely KRT—84% higher in the univariate analysis (OR=1.84, 95%, [CI]: 1.10-3.09) and 140% higher after adjustment for age, sex, and SOFA score (OR=2.40, 95% CI: 1.36-4.24). When it was determined by the creatinine cutoff criterion, there was no such difference between high and low creatinine at KRT initiation. In patients with COVID-19-related AKI, earlier KRT appears to be associated with lower in-hospital mortality. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the Sao Paulo Research Foundation (FAPESP); Grant no. 2020/06583-1). L. Andrade is the recipient of a grant from the Brazilian National Council for Scientific and Technological Development (CNPq; Grant no. 309683/2021-1). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was approved by the Institutional Review Board of the Hospital das Clinicas (Reference no. 4.129.320). Because of the retrospective nature of the study, the requirement for informed consent was waived. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors