Comparison of renal replacement therapy and renal recovery before and during the COVID-19 pandemic- A single centre observational study

Background: To compare differences in indications, management, complications and outcomes of renal replacement therapy (RRT) in COVID-19 patients compared to non-COVID critically ill patients. Methods: : We conducted a retrospective observational single centre cohort study in UK. Patients with COVID-19 requiring RRT, compared to consecutive, non-COVID-19 ICU patients requiring RRT Results: : Of 154 COVID-19 patients, 47 (30.5%) received continuous venovenous haemofiltration (CVVHF), all of whom required mechanical ventilation and vasopressor support. The requirement for RRT was related to fluid balance rather than azotaemia. Compared to 36 non-COVID-19 patients, those with COVID-19 were younger with a lower serum creatinine on hospital admission, and lesser degrees of metabolic acidosis and lactataemia before initiation of RRT. In addition, the rate of haemofilter circuit clotting was higher and duration of RRT requirement was longer. However, despite lower CVVHF exchange rates with higher serum creatinine levels following RRT initiation in the COVID-19 patients, metabolic abnormalities were corrected. Hospital mortality was 60% among COVID-19 patients requiring RRT, compared to 67% in non-COVID patients (p=0.508), and renal recovery among survivors was similar. Conclusion: The metabolic phenotype in COVID-19 patients requiring RRT differs from non-COVID-19 patients, although outcomes (mortality and renal recovery) are similar.