Incidence of major adverse kidney events after ICU admission in COVID-19 and non-COVID-19 ARDS patients

Abstract

Objectives: To compare the incidence and drivers of major adverse kidney events (MAKEs) between COVID-19 and non-COVID-19 acute respiratory distress syndrome (ARDS) patients, with a focus on long-term kidney outcomes.

Design: Retrospective cohort study.

Setting: Single-centre intensive care unit in the Midlands, UK.

Participants: 708 ARDS patients (458 COVID-19, 250 non-COVID-19).

Primary and secondary outcome measures: The primary outcome was MAKE at 365 days (MAKE-365), defined as new renal replacement therapy (RRT), estimated glomerular filtration rate (eGFR) <75% of baseline or all-cause mortality. Secondary analyses examined non-mortality MAKE components.

Results: The incidence of MAKE-365 was significantly higher in the non-COVID-19 group compared with the COVID-19 group (66% vs 39%, p<0.001), primarily driven by increased RRT initiation, followed by mortality and eGFR decline (p=0.055). Independent predictors of MAKE-365 included lower eGFR and elevated bilirubin in both groups. Age (p<0.001) and diabetes (p=0.041) were additional predictors in the COVID-19 cohort, while lower albumin (p=0.002) was significant in the non-COVID-19 group. Excluding mortality, RRT and eGFR decline remained significant drivers of MAKE outcomes in the non-COVID-19 cohort.

Conclusions: Non-COVID-19 ARDS patients face a greater risk of MAKE-365 and adverse kidney outcomes due to higher RRT requirements and mortality rates. These findings underscore the importance of tailored interventions and long-term nephrology follow-up, particularly for patients with reduced eGFR, elevated bilirubin and comorbidities like diabetes and hypoalbuminaemia.

Keywords: Acute renal failure; COVID-19; INTENSIVE & CRITICAL CARE; Intensive Care Units; Respiratory Distress Syndrome.

Figure 1. Modified CONSORT diagram. This diagram illustrates the process of participant screening and enrolment for the study. A total of 768 ICU patients were screened during the study period, of which 708 were included based on the eligibility criteria for ARDS, COVID-19 status and IMV requirements. The remaining patients were excluded for the following reasons: not receiving IMV (n=54), age <18 years (n=3) or not meeting the Berlin criteria for ARDS (n=3). AKI, acute kidney injury; ARDS, acute respiratory distress syndrome; ICU, intensive care unit; IMV, invasive mechanical ventilation; MAKEs, major adverse kidney events.

Figure 2. Forest plots of factors associated with major adverse kidney event at 365 days (MAKE-365) in COVID-19 and non-COVID-19 acute respiratory distress syndrome (ARDS) groups. Forest plots illustrating factors associated with MAKE-365 in (A) COVID-19 and (B) non-COVID-19 ARDS groups, based on multivariable logistic regression analysis. ORs with 95% CI are displayed. Significant predictors in the COVID-19 group (A) include older age, diabetes, lower eGFR and higher bilirubin levels, while significant predictors in the non-COVID-19 group (B) include lower eGFR, lower albumin and higher bilirubin levels. eGFR, estimated glomerular filtration rate.

Figure 3. The Kaplan-Meier curves for time to event of individual MAKE outcome. These Kaplan-Meier curves illustrate no difference in the initiation of RRT (A) for patients with MAKE-365 across both groups. However, the non-COVID-19 group demonstrated a higher risk of eGFR decline (B) and decreased 1-year survival (C) compared with the COVID-19 group. eGFR, estimated glomerular filtration rate; RRT, renal replacement therapy.

Figure 4. Comparison of Median eGFR on day 1 and day 365 following ICU admission in patients who received RRT within 30 days. This figure illustrates a significant difference in the median eGFR by 365 days compared with their eGFR on ICU admission, while there was no significant difference in median eGFR in non-COVID-19 patients. eGFR, estimated glomerular filtration rate; RRT, renal replacement therapy.