Acute kidney injury in COVID-19: multicentre prospective analysis of registry data

Abstract

Background: Acute kidney injury (AKI) is a common and important complication of coronavirus disease 2019 (COVID-19). Further characterization is required to reduce both short- and long-term adverse outcomes.

Methods: We examined registry data including adults with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection admitted to five London Hospitals from 1 January to 14 May 2020. Prior end-stage kidney disease was excluded. Early AKI was defined by Kidney Disease: Improving Global Outcomes creatinine criteria within 7 days of admission. Independent associations of AKI and survival were examined in multivariable analysis. Results are given as odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals.

Results: Among 1855 admissions, 455 patients (24.5%) developed early AKI: 200 (44.0%) Stage 1, 90 (19.8%) Stage 2 and 165 (36.3%) Stage 3 (74 receiving renal replacement therapy). The strongest risk factor for AKI was high C-reactive protein [OR 3.35 (2.53-4.47), P < 0.001]. Death within 30 days occurred in 242 (53.2%) with AKI compared with 255 (18.2%) without. In multivariable analysis, increasing severity of AKI was incrementally associated with higher mortality: Stage 3 [HR 3.93 (3.04-5.08), P < 0.001]. In 333 patients with AKI surviving to Day 7, 134 (40.2%) recovered, 47 (14.1%) recovered then relapsed and 152 (45.6%) had persistent AKI at Day 7; an additional 105 (8.2%) patients developed AKI after Day 7. Persistent AKI was strongly associated with adjusted mortality at 90 days [OR 7.57 (4.50-12.89), P < 0.001].

Conclusions: AKI affected one in four hospital in-patients with COVID-19 and significantly increased mortality. Timing and recovery of COVID-19 AKI is a key determinant of outcome.

Keywords: AKI; CKD; epidemiology; ethnicity; survival analysis.

GRAPHICAL ABSTRACT

FIGURE 1:

Forest plots comparing baseline risk factors for development of early AKI. IMD (1, most deprived, as reference), obesity defined as BMI ≥30 kg/m², White ethnicity as reference, CKD defined as baseline eGFR <60 mL/min/1.72 m². CEVD, cerebral vascular disease. Age modelled per 10-year increment. Effect sizes are shown as OR with 95% CIs. This model includes 1397 patients who had complete data on all covariates with 334 AKI events.

FIGURE 2:

Forest plots comparing 30-day survival by stage of early AKI compared with no early AKI, results from multivariable analysis. IMD (1, most deprived, as reference), obesity defined as BMI ≥30 kg/m², White ethnicity as reference, CKD, defined as baseline eGFR <60 mL/min/1.72 m². Age modelled per 10-year increment. Effect sizes shown as HRs with 95% CIs. This model includes 1561 patients who had complete data on all covariates with 442 deaths by Day 30.

FIGURE 3:

Kaplan–Meier plot showing survival to 90 days by stage of early AKI.