The Effect of Convalescent Plasma Infusion in the Intensive Care Unit on Mortality of COVID-19 Patients: A Retrospective Cohort Study

Objective: This study investigates the effect of convalescent plasma (CP) addition to the standard treatment on mortality in critical coronavirus disease-2019 (COVID-19) patients. Materials and Methods: This retrospective cohort study was conducted by evaluating the data of 255 critical COVID-19 patients in Marmara University Medical Faculty Hospital, Pandemic Intensive Care Unit (ICU), between April and November 2020. Results: The patients were divided into two groups, a control group that received standard treatment (153; 60.0%) versus a second group that received CP in addition to standard treatment (102; 40.0%). The ICU mortality rate was found to be lower (p<0.05) in patients receiving CP (38; 37.3%) compared to patients not receiving CP (79; 51.6%). The use of CP was found to reduce the probability of ICU mortality in patients with Acute Physiology and Chronic Health Evaluation-II (APACHE-II) score <= 10 [odds ratio (OR): 0.251; confidence interval (CI) 95%: 0.063-0.994, p=0.049) and APACHE-II score 11-14 (OR: 0.237; CI 95%: 0.066-0.844, p=0.026). CP transfusion, however, did not reduce the mortality in patients with an APACHE-II score of 15 and above. Furthermore, each day of delay in CP transfusion was found to increase the probability of mortality by 1.3 times (OR: 1.369; CI 95%: 1.155-1.622, p<0.001). Conclusion: The addition of CP to standard treatment in COVID-19 patients followed in ICU reduces mortality.