Metformin is Associated with Decreased 30-Day Mortality Among Nursing Home Residents Infected with SARS-CoV2.

This was a retrospective observational study, so it cannot show that metformin caused the lower mortality. The metformin group included residents taking metformin alone or in combination with other medications, so the study cannot separate the effect of metformin from other diabetes drugs given with it. The groups differed before adjustment, including age, diabetes-related measures, body mass index, and psychosis rates. Multivariable analysis used listwise deletion and reduced the population available for regression by approximately one-third because of missing laboratory values. The cohort was 97.3% male, so it may not apply well to nursing homes where most residents are female. The study did not review clinical records, so it could not assess why residents received specific diabetes medications, whether metformin use was appropriate, or why residents were hospitalized. Other medications with possible anti-inflammatory effects were not accounted for.

The supplied text lists research support from NIH extramural and non-U.S. government sources. It does not include an author conflict-of-interest declaration.

Do not read this as proof that metformin by itself prevents death from SARS-CoV-2 or as guidance to start metformin in infected nursing home residents. The finding is an association from a retrospective cohort, and residents on metformin differed in age, diabetes-related measures, and other health factors.