Convalescent Plasma for Patients With Severe Coronavirus Disease 2019 (COVID-19): A Matched Cohort Study

Background. The efficacy of convalescent plasma (CP) for the treatment of coronavirus disease 2019 (COVID-19) remains unclear. Methods. In a matched cohort analysis of hospitalized patients with severe COVID-19, the impact of CP treatment on in-hospital mortality was evaluated using univariate and multivariate Cox proportional-hazards models, and the impact of CP treatment on time to hospital discharge was assessed using a stratified log-rank analysis. Results. In total, 64 patients who received CP a median of 7 days after symptom onset were compared to a matched control group of 177 patients. The incidence of in-hospital mortality was 12.5% and 15.8% in the CP and control groups, respectively (P =.52). There was no significant difference in the risk of in-hospital mortality between the 2 groups (adjusted hazard ratio [aHR] 0.93, 95% confidence interval [CI].39-2.20). The overall rate of hospital discharge was not significantly different between the 2 groups (rate ratio [RR] 1.28, 95% CI.91-1.81), although there was a significantly increased rate of hospital discharge among patients 65-years-old or greater who received CP (RR 1.86, 95% CI 1.03-3.36). There was a greater than expected frequency of transfusion reactions in the CP group (2.8% reaction rate observed per unit transfused). Conclusions. We did not demonstrate a significant difference in risk of mortality or rate of hospital discharge between the CP and control groups. There was a signal for improved outcomes among the elderly, and further adequately powered randomized studies should target this subgroup when assessing the efficacy of CP treatment.

Automated summary

The study did not find a significant difference in mortality risk or hospital discharge rate between patients treated with convalescent plasma and the control group. However, there was a signal for improved outcomes among elderly patients, and a higher frequency of transfusion reactions was observed in the convalescent plasma group. Further randomized studies focusing on the elderly subgroup are recommended.