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0 0.5 1 1.5 2+ Mortality, RCTs 56% Improvement Relative Risk Mortality, non-RCTs 21% Vitamin C  Olczak-Pruc et al.  META ANALYSIS Favors vitamin C Favors control

Vitamin C Supplementation for the Treatment of COVID-19: A Systematic Review and Meta-Analysis

Olczak-Pruc et al., Nutrients, doi:10.3390/nu14194217
Oct 2022  
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Systematic review and meta analysis of 19 studies showing lower mortality with vitamin C treatment, statistically significant for RCTs but not for non-RCT studies, and longer ICU length of stay.
5 meta analyses show significant improvements with vitamin C for mortality Bhowmik, Kow, Olczak-Pruc, progression Sun, severity Bhowmik, and cases Xu.
Currently there are 64 vitamin C for COVID-19 studies, showing 20% lower mortality [10‑29%], 16% lower ventilation [-1‑31%], 15% lower ICU admission [2‑26%], 16% lower hospitalization [4‑27%], and 6% more cases [-13‑30%].
risk of death, 56.0% lower, RR 0.44, p = 0.004, RCTs.
risk of death, 21.0% lower, RR 0.79, p = 0.55, non-RCTs.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Olczak-Pruc et al., 10 Oct 2022, peer-reviewed, 8 authors.
Contact: (corresponding author),
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This PaperVitamin CAll
Vitamin C Supplementation for the Treatment of COVID-19: A Systematic Review and Meta-Analysis
Monika Olczak-Pruc, Damian Swieczkowski, Jerzy R Ladny, Michal Pruc, Raul Juarez-Vela, Zubaid Rafique, Frank W Peacock, Lukasz Szarpak
Nutrients, doi:10.3390/nu14194217
Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, caused by the severe respiratory syndrome coronavirus 2 (SARS-CoV-2), millions of people have died, and the medical system has faced significant difficulties. Our purpose was to perform a meta-analysis to estimate the effect of vitamin C on in-hospital mortality and the ICU or hospital length of stay for patients diagnosed with COVID-19. We conducted a systematic review with meta-analysis in the following databases: PubMed, Web of Science, Scopus and Cochrane Central Register of Controlled Trials. We included studies that evaluated the effect of vitamin C supplementation, compared with standard treatment in COVID-19 patients who are ≥18 y of age. Nineteen trials were included in the meta-analysis. In-hospital mortality with and without vitamin C supplementation was 24.1% vs. 33.9% (OR = 0.59; 95%CI: 0.37 to 0.95; p = 0.03), respectively. Sub-analysis showed that, in randomized clinical trials, in-hospital mortality varied and amounted to 23.9% vs. 35.8% (OR = 0.44; 95%CI: 0.25 to 0.76; p = 0.003), respectively. In the non-randomized trials, in-hospital mortality was 24.2% vs. 33.5% (OR = 0.72; 95%CI: 0.38 to 1.39; p = 0.33), respectively. The ICU length of stay was longer in patients treated with vitamin C vs. standard therapy, 11.1 (7.3) vs. 8.3 (4.7) days (MD = 1.91; 95%CI: 0.89 to 2.93; p < 0.001), respectively. Acute kidney injury in patients treated with and without vitamin C varied and amounted to 27.8% vs. 45.0% (OR = 0.56; 95%CI: 0.40 to 0.78; p < 0.001), respectively. There were no differences in the frequency of other adverse events among patients' treatment with and without vitamin C (all p > 0.05). The use of vitamin C reduces hospital mortality. The length of stay in the ICU is longer among patients treated with vitamin C. In terms of patient safety, vitamin C has an acceptable profile. Low doses of vitamin C are effective and safe. Despite some evidence of the usefulness of vitamin C in modifying the course of COVID-19, it is too early to modify guidelines and recommendations. Further studies, in particular randomized clinical trials, are necessary.
Conflicts of Interest: The authors declare no conflict of interest.
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