Association between Prolonged Intermittent Renal Replacement Therapy and All-Cause Mortality in COVID-19 Patients Undergoing Invasive Mechanical Ventilation: a Retrospective Cohort Study

Background For the coronavirus disease 2019 (COVID-19), critically ill patients had a high mortality rate. We aimed to assess the association between prolonged intermittent renal replacement therapy (PIRRT) and mortality in patients with COVID-19 undergoing invasive mechanical ventilation. Methods In this retrospective cohort study, we included all patients with COVID-19 undergoing invasive mechanical ventilation from February 12 nd to March 2 nd , 2020. All patients were followed until death or March 28 th , and all survivors were followed for at least 30 days. Results For 36 hospitalized COVID-19 patients with invasive mechanical ventilation, the mean age was 69.4 (± 10.8) years, and 30 patients (83.3%) were men. Twenty-two (61.1%) patients received PIRRT (PIRRT group) and 14 cases (38.9%) were managed with conventional strategy (non-PIRRT group). There were no differences in age, sex, comorbidities, complications, treatments and most of the laboratory findings. During median follow-up period of 9.5 (interquartile range 4.3-33.5) days, 13 of 22 (59.1%) patients in the PIRRT group and 11 of 14 (78.6%) patients in the non-PIRRT group died. Kaplan-Meier analysis demonstrated prolonged survival in patients in the PIRRT group compared with that in the non-PIRRT group (P = 0.042). The association between PIRRT and a reduced risk of mortality remained significant in three different models, with adjusted hazard ratios varying from 0.332 to 0.398. Higher levels of IL-2 receptor, TNF-α, procalcitonin, prothrombin time, and NT-proBNP were significantly associated with an increased risk of mortality in patients with PIRRT. Conclusion PIRRT may be beneficial for the treatment of COVID-19 patients with invasive mechanical ventilation. Further prospective multicenter studies with larger sample sizes are required.