Prediabetes management
Manage prediabetes initially with lifestyle changes except in the presence of certain high risk factors in which case metformin prescription is a reasonable starting point. Re-check hemoglobin A1c in six months and if lifestyle changes are insufficient to resolve prediabetes, consider starting metformin.
Clinical notes
This protocol recommends instruction on lifestyle changes for patients who screen positive for prediabetes for the first time (meaning they have an A1c from 5.7 to 6.4), recommend instruction on lifestyle changes and recommend an A1c in 6 months. Exception is patients with BMI > 35, a history of gestational diabetes, fasting glucose 110 mg/dL or greater, A1c > 6% - these should be offered metformin immediately. If patients have already been instructed with lifestyle changes, and the A1c is still in pre-diabetic range at 6 months, then recommend starting metformin. Metformin dose can be 500 mg ER, starting once a day and then increasing to the max tolerable dose (ideally 2g/day) over a few weeks (may be limited by GI adverse effects). Evidences comes from several sources. ADA Standards of Care 2023 table 2.3 suggests people with prediabetes (A1c 5.7% or higher) should be tested yearly; however expert opinion is to suggest every 6 months since lifestyle changes at a minimum should be initiated and assessment of those efforts is warranted to potentially intensify as needed. DPP (Diabetes Prevention Program) found that lifestyle modification superior to metformin (58% vs 31% vs placebo) in preventing type 2 diabetes progression at 3 years, but metformin also better than placebo and the combination of metformin plus lifestyle modification was not studied (likely some synergy). Metformin found in long term subgroup analyses of the Diabetes Prevention Program to be as effective as lifestyle modification in participants with BMI >35, history of gestational diabetes, higher fasting glucose (>110 mg/dL), higher A1c (>6.0%).
