Practice Changer: Starting metformin at lower dose may encourage persistence

  • Clinical Essentials
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This article is a transcript of a monthly podcast hosted by Neil Skolnik, MD, that covers the most practice-changing articles from the last month.  Listen to the streaming version on Univadis. 


Our next article is going to be on starting metformin at a lower dose, and how that may allow more patients to actually stay on the medication. Many patients with newly diagnosed diabetes stop their medications within 6 months. This article suggests that, by a simple change in our practice, we can halve the rate of patients stopping their metformin. Basically, this study showed that patients who were started on an initial dose of 500 mg of metformin, rather than on higher doses of metformin, had half the rate of discontinuation of their medication.

The trial used electronic medical record data to look at over 1200 individuals with diabetes who received a new prescription for metformin. About one-half of the patients were started on 500 mg daily of metformin and half on over 500 mg daily. This was a real-world study. This was not a controlled, randomized study. This was individual physicians doing what they decided was right.

Early nonpersistence of medications—meaning stopping, no more prescriptions filled after 90 days—occurred in 20% of patients. While many patients did not have any reason listed for stopping their medicines, the most common recorded reason, recorded for over 30% of patients, was side effects of their medicine. Use of metformin extended release led to fewer GI side effects recorded. Use of the extended-release formulation and doses of metformin less than or equal to 500 mg were associated with lower rates of medicine discontinuation by 38% and 46%, respectively.

After multivariate analysis, only the lower metformin dose was associated with less discontinuation of medications, with metformin doses of 500 mg decreasing discontinuation rates by 46%. That is almost halving the rate of discontinuation.

This is a practice changer for the half of us out there who are prescribing metformin at higher doses than 500 mg once daily, initially. Many people start with BID dosing, and this study suggests we’re better off starting with 500 mg once daily. I usually start with the evening meal, and then titrate upward over time.


Listen to the streaming version on Univadis.  

Neil Skolnik, MD, is Professor of Family and Community Medicine at Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, and Associate Director of the Family Medicine Residency Program at Abington Jefferson Health, also in Pennsylvania. 

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