Metformin is associated with reduced risk of mortality and morbidity in burn patients compared to insulin

Purpose

The standard of care for burned patients experiencing hyperglycemia associated with the hypermetabolic response is insulin therapy. Insulin treatment predisposes burn patients to hypoglycemia, which increases morbidity and mortality. Metformin has been suggested as an alternative to insulin therapy for glycemic control in burn patients given its safety profile, but further research is warranted. This study investigated whether metformin use in burn patients is associated with improved glycemic control and morbidity/mortality outcomes compared to insulin use alone.

Materials and methods

Using the TriNetX database, we conducted a retrospective study of burned patients who were administered insulin, metformin, or both within one week of injury. Demographic, comorbidity, and burn severity information were collected. Patients were categorized by treatment type, propensity score-matched, and compared for the following outcomes within 3 months: hyperglycemia, hypoglycemia, sepsis, lactic acidosis, and death. Statistical significance was set a priori at p ≤ 0.05.

Results

The insulin cohort was at increased risk for all outcomes (all p < 0.0001) compared to the metformin cohort, and an increased risk for sepsis, lactic acidosis, and death (all p ≤ 0.0002) compared to the insulin/metformin combination cohort. When compared to the metformin cohort, the combination cohort was at increased risk for all outcomes (all p ≤ 0.0107) except death.

Conclusions

Treatment with metformin after burn is associated with a reduced risk of morbidity and mortality compared to insulin. The combination of insulin and metformin is no more effective in reducing the risk of hyperglycemia and hypoglycemia than insulin alone but is less effective than metformin alone.