Evaluation of the convalescent plasma therapy effectiveness and the factors that influence the therapeutic outcome in hospitalized COVID-19 patients: A retrospective cohort study.

Abstract

Background: As an effective antiviral therapy is not available for the treatment of the current rapidly and continuously spreading coronavirus disease (COVID-19), it is very crucial to find an alternative treatment strategy. Convalescent plasma (CP) therapy has been used for prevention and treatment of many emerging infectious diseases, however, the results of current studies on CP in COVID-19 are not consistent. Therefore, this study aimed to evaluate the effectiveness of CP therapy in hospitalized patients with COVID-19, while evaluating patient and donor-related factors that might influence the therapeutic outcome. Methods: We conducted a retrospective cohort study on 312 patients with either severe or critical COVID-19, who were admitted to Al-Hakeem and Al-Amal hospitals in Al-Najaf city, Iraq from June to August 2020. The patients were allocated to either the plasma therapy group (152 patients) who received CP combined with standard therapy or the standard therapy group (160 patients). The outcome measures were the 21-day mortality rate and time to clinical improvement. Results: The overall cumulative survival rate was significantly higher in patients who received CP compared to standard therapy alone at 21 days (68.3% vs. 46.8%, p-value = 0.010), with mean survival at 17.6 vs. 15.3 days, (p-value = 0.010). In multivariate analysis, the plasma therapy effect was an independent predictor of survival (adjusted hazard ratio, 95% confidence interval: 0.368, 0.177 – 0.765). In terms of clinical improvement, the use of CP resulted in shorter clinical improvement (median duration of improvement: 8 vs. 11 days, p-value = 0.007), with 74.3% improvement rate after 21 days in CP compared to 65.0% in standard therapy. Conclusions: Therapy with CP in combination with standard therapy, independently improved survival in hospitalized patient with severe or critical COVID-19.