Time-Dependent Outcomes of Convalescent Plasma in Early COVID-19: A Single-Center Cohort with a Host-Pathogen...

Evidence on COVID-19 convalescent plasma (CCP) is mixed. We examined associations between CCP administration and in-hospital outcomes among patients hospitalized during early pandemic waves in Poland.

We conducted a retrospective, single-center cohort study of adults hospitalized with COVID-19 between October 2020 and January 2021. Patients receiving CCP were compared with contemporaneous controls without CCP. Primary outcomes were in-hospital mortality and discharge alive. Requirement for invasive mechanical ventilation/intubation was summarized descriptively because timing of intubation was not reliably available. Group comparisons used χ²/Fisher's exact tests and t-test/Mann-Whitney U tests as appropriate. Associations with mortality and discharge were evaluated using logistic regression: (i) a prespecified age-adjusted model and (ii) an exploratory prognostic model including in-hospital treatments and severity markers (systemic glucocorticoids, remdesivir, oxygen therapy, and antibiotic use), interpreted prognostically rather than causally.

The cohort included 224 patients (CCP, n = 92; controls, n = 132); outcome status was missing for eight controls. Baseline demographics, comorbidities, and admission laboratory values were broadly comparable between groups. Crude in-hospital mortality was 25% in the CCP group (23/92) versus 42% in controls (52/124; p = 0.010), and discharge alive occurred in 66% versus 50%, respectively (p = 0.022). Invasive mechanical ventilation/intubation was required in 12.0% of CCP recipients and 4.5% of controls (p = 0.071). In age-adjusted models, CCP was associated with lower odds of in-hospital death. In exploratory prognostic models incorporating systemic glucocorticoids, remdesivir, oxygen therapy, and antibiotic use, CCP remained associated with lower odds of death and higher odds of discharge alive.

In this early-wave retrospective cohort, CCP administration was associated with lower in-hospital mortality and higher discharge rates. Exploratory analyses adjusted for concomitant in-hospital therapies and severity markers should be interpreted as prognostic associations rather than evidence of causal efficacy.