Efficacy of therapeutic plasma exchange in patients with severe COVID-19: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis predominantly composed of non-randomized studies (12 non-RCTs, 1 RCT)
PubMed 36905184 · doi:10.1002/rmv.2435
What was done
A systematic review and meta-analysis (PROSPERO CRD42022316331) searched six databases through June 1, 2022, for studies evaluating therapeutic plasma exchange (TPE) versus standard treatment in severe COVID-19 patients. Risk of bias was evaluated using the Cochrane RoB tool, ROBINS-I, and the Newcastle-Ottawa Scale. Effect sizes were pooled using random-effects models as standardized mean differences (SMD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes.
What was found
Across 13 included studies (1 RCT, 12 non-RCTs; total n = 829), low-quality evidence from mixed-design studies showed TPE was associated with reduced mortality (RR 0.51, 95% CI [0.35, 0.74]), lower IL-6 (SMD -0.91, 95% CI [-1.19, -0.63]), and lower ferritin (SMD -0.51, 95% CI [-0.80, -0.22]). Moderate-quality evidence from the single RCT indicated TPE reduced LDH (SMD -1.09, 95% CI [-1.59, -0.60]), D-dimer (SMD -0.86, 95% CI [-1.34, -0.37]), and ferritin (SMD -0.70, 95% CI [-1.18, -0.23]), while increasing absolute lymphocyte count (SMD 0.54, 95% CI [0.07, 1.01]).
Why it matters
This review synthesizes available comparative data suggesting TPE may mitigate systemic hyperinflammation and decrease mortality in severe COVID-19. However, the findings serve primarily as hypothesis-generating support for larger prospective randomized trials.
Limits
The primary limitation is the heavy predominance of non-randomized study designs (12 of 13 studies), creating substantial risk of confounding and selection bias. Only a single RCT was available, sample size overall was modest (829 total patients), and specific adverse events or procedure-related complications were not detailed in the abstract.
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