Propensity score-matched case–control study of convalescent plasma in treatment of patients with moderate and severe COVID-19

Abstract

Background: Convalescent plasma (CP) in coronavirus disease 2019 (COVID-19) acts as a source of neutralizing antibodies that could provide passive immunity. There still exists uncertainty on the safety and efficacy of CP as a therapeutic option in COVID-19. This study reports on the effectiveness of CP therapy (CPT) in patients with moderate and severe COVID-19 in an Indian cohort. Methodology: This propensity score matched (PSM) case–control study included a total of 477 adult patients with COVID-19 (≥18 years of age) with moderate and severe disease out of which 181 patients received CP having neutralizing antibody titers ≥1:40 (PRNT/MNT). PSM with an optimal algorithm was performed, matching cases (CP recipients) on baseline patient characteristics to select (178) controls in a 1:1 ratio. Analysis included logistic regression for the whole-patient sample, conditional logistic regression for PSM sample, and competing risk approach for time-to-event analysis. Primary outcome was in-hospital all-cause mortality. Results: Greater odds of clinical improvement were observed among CP recipients on day 7, but no significant differences were observed in the clinical status on day 14. Mortality was lower in patients treated with CP; however, the difference was not statistically significant. Logistic-regression analysis for whole-patient sample and conditional logistic regression for PSM sample showed no significant mortality benefit of CP both in the unadjusted and covariate-adjusted models. No significant mortality benefit was observed among CP recipients in the survival analysis. Conclusion: CPT in COVID-19 appears to have some benefit as evinced by greater odds of clinical recovery on day 7, however, offers no survival benefit.