Convalescent plasma treatment is associated with lower mortality and better outcomes in high-risk COVID-19 patients – propensity-score matched case-control study

OBJECTIVE: This study aimed to investigate the efficacy and safety of convalescent plasma (CP) transfusion in a group of high-risk COVID-19 patients. METHODS: This prospective study included 204 patients from a single tertiary-care hospital, hospitalized with COVID-19, of whom 102 were treated with CP administration and standard care (PG) and 102 others who received standard care only (CG). The CG was selected from 336 hospitalized patients using the propensity-score matching (PSM) technique using age, MEWS score, and comorbidities. The primary outcome was mortality rate; secondary outcomes were the requirement of a ventilator, length of ventilator need, length of intensive care unit (ICU) stay, and length of overall hospital confinement. Additionally, parameters predicting death in COVID-19 patients were identified. RESULTS: Findings confirmed a significantly lower mortality rate in the PG versus the CG (13.7% vs. 34.3 %, p = 0.001) and a significant difference in the cumulative incidence of death between the two groups (p < 0.001). CP treatment was associated with lower risk of death (OR = 0.25 CI(95) [0.06; 0.91], p = 0.041). There were no significant differences in ICU stay, ventilator time, and hospitalization time between the two groups. CONCLUSIONS: A significantly lower mortality rate was observed in the group of patients treated with CP. Age, presence of cardiac insufficiency, active cancer, a ventilator requirement, and length of hospitalization significantly increased the risk of death in both groups. Our study shows that CP affords better outcomes when administrated in the earlier stage of high-risk COVID-19 disease.