Time-course modifications of management and outcomes of critically ill COVID-19 patients requiring CRRT

ABSTRACT

Background: Occurrence of acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT) in patients with Coronavirus disease-19 (COVID-19) is associated with an elevated mortality rate. However, due to the high clinical impact, the COVID-19 has been the object of extensive studies that have potentially changed disease presentation and outcomes. In this regard, the development of vaccination has shown high effectiveness in preventing severe disease, hospitalization, and death related to COVID- 19. Thus, this study aimed at investigating whether any difference exists in clinical presentation, management, and mortality of COVID- 19 critically ill patients requiring CRRT before and after the vaccination campaigns. Method(s) We performed a retrospective study on critically ill adult COVID-19 patients with AKI undergoing CRRT in the Intensive care Unit (ICU) before (from March 2020 to March 2021- 1st Group) and after (from April 2021 to March 2022- 2nd Group) the availability of COVID-19 vaccines. Result(s) Overall, we considered 111 patients, aged 64 (62-65) years, 75.7 % males. The main comorbidities were diabetes (DM), lung diseases, cardiovascular disease, and hypertension. Among them, 88 (79%) were in 1st and 23 (21%) in the 2nd group, respectively. The 2nd group included 5 (22%) patients vaccinated against COVID-19, a percentage significantly lower than that reported for the Italian age-matched general population (i.e. 84.4%) There were no significant differences in general characteristics, such as in comorbidities, except for a higher prevalence of hypertension in the 1st group. Lab examinations at ICU admission were similar between the two groups except for procalcitonin and lactate dehydrogenase, which were higher in the 2nd group. While ventilation strategies were not different between the two groups, ECMO was used in a significantly higher number of patients in the 2nd group (30 vs 4%, p<0.001). Regarding specific drug therapy, while hydroxychloroquine was abandoned in the 2nd group, the use of heparin significantly increased, and monoclonal antibodies were introduced in the clinical practice (and prescribed in 4/23 patients of the 2nd group). CRRT was mostly provided according to CVVHD modality (about 87% in both groups) and sepsis devices were used in 45.4 and 56.5% of the 1st and the 2nd group, respectively. Looking at the outcomes, in terms of length of ICU stay and mortality, we found no significant difference between the two groups. Indeed, 58 (66%) and 15 (68%) patients died in ICU in the 1st and the 2nd group, respectively. Finally, considering the whole population at multivariate Cox regression, the length of ICU hospitalization, days on CRRT, invasive ventilation, and DM were independently related to the 90-day mortality rate. Conclusion(s) Despite the recent acquisitions and progress in COVID-19 pathogenesis and management, when compared with patients undergoing CRRT during the first phases of the pandemic, patients critically ill COVID-19 requiring CRRT after the availability of vaccines presented similar clinical characteristics and poor outcomes. This population was characterized by a low vaccination rate when compared with the general population, suggesting that this factor could be a key determinant of the clinical course of these patients. These data further reinforce the concept that in absence of established effective treatments, the most useful strategy to reduce COVID-19-related mortality is constituted by the prevention of the severe form of the disease, through the wide diffusion and universal implementation of vaccines.