ABSTRACT
Background Severely ill people with COVID-19 are at risk of acute kidney injury treated with renal replacement therapy (AKI-RRT). Understanding of risk factors and outcomes for AKI-RRT is incomplete. Methods We prospectively collected data on the incidence, demographics, area of residence, time course, outcomes, and associated risk factors for all COVID-19 AKI-RRT cases during the first 2 waves of the pandemic in Ontario, Canada Results There were 271 people with AKI-RRT, representing 0.1% of all diagnosed SARS-CoV-2 cases. These included 10% of SARS-CoV-2 admissions to intensive care units (ICU). Median age was 65 years, with 11% under 50, 76% were male, 47% non-white, and 48% had diabetes. Overall, 59% resided in the quintile of Ontario neighborhoods with the greatest ethnocultural composition and 51% in the 2 lowest income quintile neighborhoods. Mortality was 58% at 30 days after RRT initiation, and 64% at 90 days. By 90 days, 20% of survivors remained RRT-dependent and 31% were still hospitalized. On multivariable analysis, people aged over 70 had higher mortality (odds ratio (OR) 2.4, 95% CI: 1.3, 4.6). Cases from the second versus the first COVID-19 wave were older, had more baseline co-morbidity, and were more likely to initiate RRT over 2 weeks after SARS-CoV-2 diagnosis (34% vs 14%, p < 0.001). Conclusions AKI-RRT is common in COVID-19 ICU admissions. Residency in areas with high ethnocultural composition and lower socioeconomic status are strong risk factors. Late onset AKI-RRT was more common in the second wave. Mortality is high and 90-day survivors have persisting high morbidity. Graphical Graphical