Metformin Prescription Orders among Patients with Prediabetes in a National Network of Federally Qualified Health Centers.

Abstract

Clinical trials of adults with prediabetes demonstrate that metformin can prevent or delay the risk of developing type 2 diabetes by approximately 30%. The association between socioeconomic disadvantage and elevated diabetes risk underscores the importance of using metformin in this high-risk group. To examine the prevalence of metformin prescriptions among patients with prediabetes served by federally qualified health centers (FQHCs), the largest national system of primary care clinics in socioeconomically disadvantaged communities. Retrospective cohort study using 2008-2019 electronic health record data from a national FQHC network. Patients with prediabetes were identified by the presence of: ≥ 1 diagnosis code; or ≥ 2 glycemic test results in the prediabetes range. We excluded patients with prior metformin prescription orders and those with prior evidence of diabetes by diagnosis code or two glycemic test results in the diabetes range. We examined metformin prescription orders, overall, and by patient characteristics including age and body mass index (BMI). A total of 59,232 FQHC patients were found to have prediabetes, of whom 48.4% reported Hispanic ethnicity, 27.2% reported Black race, 22.5% had Medicaid insurance, and 33.1% were uninsured. Within one and five years of prediabetes diagnosis, metformin was prescribed for 3.0% and 6.1% of patients, respectively. In multivariate analyses, increasing BMI was the strongest predictor of metformin prescription orders. Disparities in metformin prescription rates were observed among FQHCs patients from racial minority groups relative to White patients. Metformin prescriptions for prediabetes are rare among FQHC patients. Prescribing rates were higher among patients with elevated BMI, and lower among patients from racial minority groups. Further research is needed to understand reasons for low metformin use in this population and promote clinical guidelines for diabetes prevention in FQHCs.