Implementation and Evaluation of the "Metformin First" Protocol for Management of Gestational Diabetes

Although metformin has traditionally been avoided in pregnancy, evidence now supports its safety and efficacy for management of gestational diabetes mellitus (GDM). The primary objective of this study was to evaluate the clinical impact of a metformin-based approach for GDM management through assessment of pregnancy outcomes, clinic efficiency and patient satisfaction.

A retrospective chart review was conducted of new GDM patients seen before (January to July 2015) and after (January to September 2016) implementation of the "Metformin First" (MF) protocol. A prospective patient survey was also administered and responses were compared with a similar survey from 2013 (acting as a historical control).

Of the 264 patients included in the chart review, 90 were seen in the pre-MF period and 174 in the post-MF period. There were no significant differences in rates of pregnancy complications (obstructed labour, infants born large for gestational age, neonatal intensive care unit admissions and infant hypoglycemia) between the 2 study periods. Blood glucose control was also comparable and satisfactory across both time periods. Of the 65 patients initially started on metformin, 18 (28%) required supplemental insulin therapy. Nonetheless, overall percentage of patients started on insulin dropped significantly (33% in 2015 vs 17% in 2016, p=0.003). Patient satisfaction scores at the clinic also increased following implementation of the MF protocol (4.68/5 in 2016 vs 4.3/5 in 2013, p=0.014).

Introduction of the MF protocol, which gave patients an informed choice between insulin and metformin, was associated with similar glycemic control and pregnancy outcomes, but improved patient satisfaction and clinic efficiency.