Supplementary Material for: The efficacy of hemoperfusion in severe COVID-19 patients: A systematic review and meta-analysis

Objective: The objective of this study was to conduct a meta analysis and systematic review to assess the efficacy of the hemoperfusion in patients with severe COVID-19. Data Sources: A comprehensive search for candidate publications was performed using PubMed, Cochrane Library, and Embase. Study Selections: Studies investigating the effect of hemoperfusion on mortality among severe COVID-19 patients were selected, including randomized controlled trials(RCTs), non-randomized controlled trials, and observational studies with control groups. The primary endpoint was the longest reported mortality, while the secondary endpoints were the length of stay, ICU stay, P/F ratio, and CRP. Data Extraction: The Cochrane test (Q) and Isquare (I2) test were used to quantify heterogeneity among the studies. The fixedeffect model (Mantel–Haenszel method) would be selected when there is no heterogeneity (P > 0.10 and I2 < 50%), whereas the randomeffect model (DerSimonian–Laird method) was used in obvious heterogeneity (P ≤ 0.10 and I2 ≥ 50%). Data are presented as risk ratio(RR); 95% confidence intervals(CIs); p values; I2. Data synthesis: Of the 127 articles retrieved, 14 were selected for this study including 405 patients in the HP group and 518 patients in the control group. There was no statistically significant difference in mortality between the hemoperfusion and the control groups (RR 0.81 95%CI[0.71, 0.93]; p = 0.15 > 0.05; I2 = 68.2%). The results of the subgroup analysis of hemoperfusion with HA series indicated a reduction in the mortality of patients with COVID-19 (RR 0.60 [0.46, 0.78]; p < 0.0001; I2 =0.0%). The hemoperfusion (HP) group had a longer length of stay compared with the control group (WMD 5.25[2.53, 7.97]days; p < 0.05; I2 = 28.0%), but not the ICU stay (ES 1.33[-2.86, 5.53]days; p = 0.53; I2 = 85.5%). After hemoperfusion, the P/F ratio (WMD 95.79[74.46, 117.12]mmHg; p < 0.05; I2 = 5.8%) increased, while CRP (WMD -44.03[-68.97, -19.09]mg/L; p < 0.05; I2 = 86.9%) decreased.