Clinical Characteristics, Management and Outcomes of Critically ill COVID-19 Patients Undergoing CRRT: Comparison Between the First Two Pandemic Waves

ABSTRACT

BACKGROUND AND AIMS Acute kidney injury (AKI) is a common complication of coronavirus disease-19 (COVID-19), which, particularly in critically ill patients requiring continuous renal replacement therapy (CRRT), is associated with an elevated mortality risk [1, 2]. However, knowledge about COVID-19 pathogenesis and management is evolving, and clinical practice is changing rapidly. Here, we evaluated if this process had an impact on the management and outcome of AKI patients. METHODS We performed a retrospective observational study on critically ill adult COVID-19 patients who received CRRT in the intensive care unit (ICU) during the first two pandemic waves before the availability of COVID-19 vaccines the first one from March to August 2020 (first) and the second one (second) from September to December 2020. RESULTS Overall, we considered 63 patients, aged 65 (60–69) years, 76.2% males. The main comorbidities were diabetes (DM), cardiovascular disease (CVD) and chronic kidney disease (CKD). Among them, 28 (44%) were in the first group and 35 (66%) in the second group. There were no significant differences in general characteristics, such as in comorbidities, except for a higher prevalence of CVD in the first group (Fig. 1). Lab examinations at ICU admission, including serum creatinine level (sCr), were not different between the two groups. While all patients required respiratory support, non-invasive ventilation was more prevalent in the second wave. Notably, during this period, decapneization combined with CRRT was introduced. Regarding drugs, we found that in the second group, hydroxychloroquine was abandoned, tocilizumab use was reduced and heparin administration significantly increased. The AKI time course was similar between the patients of the two waves (Fig. 2). There were no significant differences in CRRT techniques. However, in the second, the use of additional CRRT-devices, in particular adsorption-based filters, significantly increased. In most cases, citrate anticoagulation was used in both groups. Looking at the outcomes, we found no significant difference between the two waves. Indeed, 17 (60.2%) and 22 (62.8%) patients died in the ICU in the first and second groups, respectively. The length of ICU hospitalization, days on CRRT, invasive ventilation and DM were significantly related to overall mortality;time of ICU hospitalization was the only remaining significant at multivariate Cox regression. Overall, 21 (33%) patients survived hospitalization. At the 6 months after the discharge, 3 of them died, 3 were on HD and 15 were dialysis-free, even if 6 of them presented CKD.FIGURE 1 Clinical characteristics and ICU management of critically ill COVID-19 patients undergoing CRRT.FIGURE 2 Kidney function and management of critically ill COVID-19 patients undergoing CRRT. CONCLUSION Our data confirm the high complexity and mortality of COVID-19 patients undergoing CRRT. Comparing the first two pandemic waves, we found that the patients also presented similar characteristics in terms of renal function and AKI time course. Regarding treatments, we observed some significant modifications in the management of ventilation, drug administration and dialysis membranes, mainly because of the results of ongoing clinical trials. However, these changes did not impact patients’ outcomes. These data support the view that only game-change strategies, such as vaccination or infection-specific drugs, may impact the presentation and outcome of COVID-19 patients undergoing CRRT. Finally, patients surviving this condition deserve special attention in the follow-up.