Inpatient Metformin Utilization and Post-hospitalization Clinical Outcomes: An Observational Cohort Study

Area of Science:

• Internal Medicine
• Endocrinology
• Clinical Pharmacology

Background:

• Metformin is a primary treatment for diabetes, yet its inpatient use is debated.
• Guidelines often suggest withholding oral diabetes medications during hospitalization.
• Concerns exist regarding potential harm from stopping metformin, including increased insulin use and post-discharge complications.

Purpose of the Study:

• To evaluate the association between continuing metformin during hospitalization and key post-hospitalization outcomes.
• To assess the impact of inpatient metformin use on hypoglycemia, insulin prescriptions, readmissions, and mortality.

Main Methods:

• An observational cohort study emulating a target trial was conducted from January 2016 to January 2022.
• The study included adult patients with type 2 diabetes admitted for common medical conditions.
• Continuation of outpatient metformin prescriptions during hospitalization was the primary exposure of interest.

Main Results:

• In a propensity-matched cohort of 67,162 hospitalizations, continuing metformin was associated with a reduced risk of 90-day hypoglycemia (OR 0.83) and insulin prescriptions at discharge (OR 0.89).
• Metformin continuation also correlated with significantly lower rates of 90-day readmissions (OR 0.96) and mortality (OR 0.86).
• Statistical significance was observed for all key outcomes (p < 0.05).

Conclusions:

• Continuation of metformin during hospitalization for type 2 diabetes patients is associated with improved post-discharge outcomes.
• These findings suggest a potential benefit in reconsidering current clinical guidelines that recommend withholding metformin.
• Inpatient metformin use may reduce the need for insulin and lower risks of hypoglycemia, readmissions, and mortality.