AKI Treated with Renal Replacement Therapy in Critically Ill Patients with COVID-19

Abstract

Background: AKI is a common sequela of coronavirus disease 2019 (COVID-19). However, few studies have focused on AKI treated with RRT (AKI-RRT).

Methods: We conducted a multicenter cohort study of 3099 critically ill adults with COVID-19 admitted to intensive care units (ICUs) at 67 hospitals across the United States. We used multivariable logistic regression to identify patient-and hospital-level risk factors for AKI-RRT and to examine risk factors for 28-day mortality among such patients.

Results: A total of 637 of 3099 patients (20.6%) developed AKI-RRT within 14 days of ICU admission, 350 of whom (54.9%) died within 28 days of ICU admission. Patient-level risk factors for AKI-RRT included CKD, men, non-White race, hypertension, diabetes mellitus, higher body mass index, higher d-dimer, and greater severity of hypoxemia on ICU admission. Predictors of 28-day mortality in patients with AKI-RRT were older age, severe oliguria, and admission to a hospital with fewer ICU beds or one with greater regional density of COVID-19. At the end of a median follow-up of 17 days (range, 1-123 days), 403 of the 637 patients (63.3%) with AKI-RRT had died, 216 (33.9%) were discharged, and 18 (2.8%) remained hospitalized. Of the 216 patients discharged, 73 (33.8%) remained RRT dependent at discharge, and 39 (18.1%) remained RRT dependent 60 days after ICU admission.

Conclusions: AKI-RRT is common among critically ill patients with COVID-19 and is associated with a hospital mortality rate of >60%. Among those who survive to discharge, one in three still depends on RRT at discharge, and one in six remains RRT dependent 60 days after ICU admission.

Keywords: COVID-19; acute kidney injury; acute renal failure; clinical epidemiology; dialysis; renal replacement therapy; risk factors.

Graphical abstract

Figure 1.

Flowchart of study population. This figure shows the number of patients with and without AKI-RRT and, among those with AKI-RRT, the number of patients who died, were discharged, and were still hospitalized at last follow up.

Figure 2.

Patients with AKI-RRT have higher 28-day mortality than patients without AKI-RRT. This figure shows the 28-day mortality of patients with AKI-RRT, those with AKI who were not treated with RRT, and those without AKI across categories of age (A), sex (B), race (C), comorbidities (D), and hospital characteristics; number of ICU beds (E) and regional density of COVID-19 (F). CAD, coronary artery disease; CHF, congestive heart failure.

Figure 3.

Patient- and hospital-level characteristics and AKI-RRT. The frequency of patient- and hospital-level characteristics in the overall cohort (n=3099) is displayed in blue, and the proportion of patients who developed AKI-RRT within 14 days following ICU admission is displayed in red. Smoking includes both current and former smoking. ACE-I, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; CAD, coronary artery disease; CHF, congestive heart failure; HTN, hypertension; MRA, mineralocorticoid receptor antagonist.

Figure 4.

Multivariable model for AKI-RRT and RRT/death. This figure shows (left panel) the odds of AKI-RRT and (right panel) the composite of AKI-RRT or death (RRT/death) within 14 days following ICU admission according to patient- and hospital-level characteristics. A total of 637 of 3099 patients (20.6%) developed AKI-RRT. A total of 1205 of 3099 patients (38.9%) developed RRT/death, of whom 413 (34.3%) developed AKI-RRT and did not die, 568 (47.1%) died without AKI-RRT, and 224 (18.6%) both developed AKI-RRT and died. Unless otherwise indicated, severity of illness covariates were selected as the worst value on ICU day 1 or 2. SOFA, Sequential Organ Failure Assessment.

Figure 5.

The incidence of AKI-RRT varies by hospital. Interhospital variation in AKI-RRT. Risk- and reliability-adjusted rates of AKI-RRT within 14 days following ICU admission. (A) is unadjusted. (B) is adjusted for patient-level characteristics. (C) is adjusted for both patient- and hospital-level characteristics, including number of ICU beds and regional density of COVID-19.

Figure 6.

Multivariable model for 28-day mortality in patients with AKI-RRT. Unless otherwise indicated, severity of illness covariates were selected on the day of RRT initiation or if unavailable, the day prior. CRRT, continuous RRT; SOFA, Sequential Organ Failure Assessment.

Figure 7.

Incidence of AKI at 3, 7, and 14 days from ICU admission. For each time period, patients were categorized according to the highest stage of AKI achieved.