Statistically significant lower risk is seen for mortality, ventilation, ICU admission, hospitalization, progression, and recovery. 54 studies from 51 independent teams in 18 countries show statistically significant improvements.
Meta analysis using the most serious outcome reported shows 29% [25‑33%] lower risk. Results are similar for higher quality and peer-reviewed studies and better for Randomized Controlled Trials.
Results are robust — in exclusion sensitivity analysis 68 of 88 studies must be excluded to avoid finding statistically significant efficacy in pooled analysis.
Most studies analyze existing use with diabetic patients, and many results may be subject to
confounding by indication — metformin is typically used early in the progression of type 2 diabetes. Prophylaxis results typically include continuing use after infection and hospitalization, and greater benefit is seen for more serious outcomes. The TOGETHER RCT shows 27% lower mortality. While not statistically significant,
p = 0.53, this is consistent with the mortality results from all studies, 34% [29‑38%].
No treatment or intervention is 100% effective. All practical, effective, and safe means should be used based on risk/benefit analysis. Multiple treatments are typically used in combination, and other treatments are more effective.
All data to reproduce this paper and sources are in the appendix. Other meta analyses show significant improvements with metformin for mortality Hariyanto, Kan, Kow, Li, Lukito, Ma, Oscanoa, Parveen, Petrelli, Poly, Schlesinger, Yang, hospitalization Li, progression Yang, and severity Petrelli, Schlesinger.
13 meta analyses show significant improvements with metformin for mortality
Hariyanto,
Kan,
Kow,
Li,
Lukito,
Ma,
Oscanoa,
Parveen,
Petrelli,
Poly,
Schlesinger,
Yang,
hospitalization
Li,
progression
Yang, and
severity
Petrelli,
Schlesinger.
Covid Analysis et al., Apr 2024, preprint, 1 author.
