Retrospective 6,256 COVID-19+ diabetes patients in the USA, showing lower mortality with existing metformin treatment, statistically significant only for women.
Bramante et al., 12/3/2020, retrospective, database analysis, USA, North America, peer-reviewed, 17 authors.
risk of death, 7.2% lower, RR 0.93, p = 0.15, treatment 394 of 2333 (16.9%), control 791 of 3923 (20.2%), odds ratio converted to relative risk, PSM, all patients.
risk of death, 24.1% lower, RR 0.76, p = 0.02, treatment 1129, control 2173, PSM, women, RR approximated with OR.
risk of death, 4.3% lower, RR 0.96, p = 0.69, treatment 1204, control 1750, Cox proportional hazards, men, RR approximated with OR.
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.