Efficacy of therapeutic plasma exchange in patients with severe COVID-19: A systematic review and meta-analysis

We conducted this systematic review and meta-analysis to evaluate the existing evidence and to quantitatively synthesise evidence on the impact of therapeutic plasma exchange (TPE) on severe COVID-19 patients. This systematic review and meta-analysis protocol was prospectively registered on PROSPERO (CRD42022316331). We systemically searched six electronic databases (PubMed, Scopus, Web of Science, ScienceDirect, clinicaltrial.gov, and Cochrane Central Register of Controlled Trials) from inception until 1 June 2022. We included studies comparing patients who received TPE versus those who received the standard treatment. For risk of bias assessment, we used the Cochrane risk of bias assessment tool, the ROBINS1 tool, and the Newcastle Ottawa scale for RCTs, non-RCTs, and observational studies, respectively. Continuous data were pooled as standardized mean difference (SMD), and dichotomous data were pooled as risk ratio in the random effect model with the corresponding 95% confidence intervals (CI). Thirteen studies (one randomized controlled trials (RCT) and 12 non-RCTs) were included in the meta-analysis, with a total of 829 patients. There is a moderate-quality evidence from one RCT that TPE reduces the lactic dehydrogenase (LDH) levels (SMD -1.09, 95% CI [-1.59 to -0.60]), D-dimer (SMD -0.86, 95% CI [-1.34 to -0.37]), and ferritin (SMD -0.70, 95% CI [-1.18 to -0.23]), and increases the absolute lymphocyte count (SMD 0.54, 95% CI [0.07-1.01]), There is low-quality evidence from mixed-design studies that TPE was associated with lower mortality (relative risk 0.51, 95% CI [0.35-0.74]), lower IL-6 (SMD -0.91, 95% CI [-1.19 to -0.63]), and lower ferritin (SMD -0.51, 95% CI [-0.80 to -0.22]) compared to the standard control. Among severely affected COVID-19 patients, TPE might provide benefits such as decreasing the mortality rate, LDH, D-dimer, IL-6, and ferritin, in addition to increasing the higher absolute lymphocyte count. Further well-designed RCTs are needed.

The potential role of vitamin E in patients with glucose-6-phosphate dehydrogenase deficiency: A systematic review and meta-analysis

BACKGROUND

As an antioxidant, vitamin E (VitE) may benefit the erythrocytes by protecting glutathione from oxidation by free radicals and peroxide-generating processes.

METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines when reporting this systematic review. We searched 6 electronic databases (PubMed, Scopus, Web of Science, and Cochrane Library) until May 8, 2022. We included all relevant studies. According to the study design, the Cochrane assessment tool (Risk of Bias 2), Risk Of Bias In Non-randomized Studies - of Interventions checklists, and National Institutes of Health tools were used to assess the risk of bias.Continuous data were pooled as a mean difference (MD) with a relative 95% confidence interval. The protocol was registered on PROSPERO (CRD42022333848).

RESULTS

Six studies were included in the meta-analysis with a total of 181 patients. Compared with the control group, VitE significantly improved the hemoglobin level for chronic hemolysis (MD = 2.72 g/dL, P < .0001) and for acute hemolysis (MD = 1.18 g/dL, P < .0001). It also decreased the reticulocyte level for chronic hemolysis (MD = -1.39 P < .0001) and for acute hemolysis (MD = -1.42%, P < .0001). For before and after studies, the use of VitE significantly improved the level of packed cell volume (MD = 0.56%, P < .00001), red blood cell half-life (MD = 2.19 days, P < .0001), and decreased the reticulocytes level (MD = -1.41%, P < .00001).

CONCLUSION

Among patients with glucose-6-phosphate dehydrogenase deficiency, VitE might provide benefits such as increasing the hemoglobin, packed cell volume levels, red blood cell half-life, and decreasing the reticulocyte level, so reducing hemolysis. Further high-quality, well-designed randomized controlled trials are recommended.