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.