Nearly half of adults prescribed metformin after a new diagnosis of type 2 diabetes have stopped taking it by 1 year, new data show.
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The findings, from a retrospective analysis of administrative data from Alberta, Canada, during 2012-2017, also show that the fall-off in metformin adherence was most dramatic during the first 30 days, and in most cases, there was no concomitant substitution of another glucose-lowering drug.
While the majority with newly diagnosed type 2 diabetes were prescribed metformin as first-line therapy, patients started on other agents incurred far higher medication and health care costs.
The data were recently published online in Diabetic Medicine by David J. T. Campbell, MD, PhD, of the University of Calgary (Alta.), and colleagues.
“We realized that even if someone is prescribed metformin that doesn’t mean they’re staying on metformin even for a year ... the drop-off rate is really quite abrupt,” Dr. Campbell said in an interview. Most who discontinued had A1c levels above 7.5%, so it wasn’t that they no longer needed glucose-lowering medication, he noted.
People don’t understand chronic use; meds don’t make you feel better
One reason for the discontinuations, he said, is that patients might not realize they need to keep taking the medication.
“When a physician is seeing a person with newly diagnosed diabetes, I think it’s important to remember that they might not know the implications of having a chronic condition. A lot of times we’re quick to prescribe metformin and forget about it. ... Physicians might write a script for 3 months and three refills and not see the patient again for a year ... We may need to keep a closer eye on these folks and have more regular follow-up, and make sure they’re getting early diabetes education.”
Side effects are an issue, but not for most. “Any clinician who prescribes metformin knows there are side effects, such as upset stomach, diarrhea, and nausea. But certainly, it’s not half [who experience these]. ... A lot of people just aren’t accepting of having to take it lifelong, especially since they probably don’t feel any better on it,” Dr. Campbell said.
James Flory, MD, an endocrinologist at Memorial Sloan Kettering Cancer Center, New York, said in an interview that about 25% of patients taking metformin experience gastrointestinal side effects.
Moreover, he noted that the drop-off in adherence is also seen with antihypertensive and lipid-lowering drugs that have fewer side effects than those of metformin. He pointed to a “striking example” of this, a 2011 randomized trial published in the New England Journal of Medicine, and as reported by this news organization, showing overall rates of adherence to these medications was around 50%, even among people who had already had a myocardial infarction.
“People really don’t want to be on these medications. ... They have an aversion to being medicalized and taking pills. If they’re not being pretty consistently prompted and reminded and urged to take them, I think people will find rationalizations, reasons for stopping. ... I think people want to handle things through lifestyle and not be on a drug,” noted Dr. Flory, who has published on the subject of metformin adherence.
“These drugs don’t make people feel better. None of them do. At best they don’t make you feel worse. You have to really believe in the chronic condition and believe that it’s hurting you and that you can’t handle it without the drugs to motivate you to keep taking them,” Dr. Flory explained.
Communication with the patient is key, he added.
“I don’t have empirical data to support this, but I feel it’s helpful to acknowledge the downsides to patients. I tell them to let me know [if they’re having side effects] and we’ll work on it. Don’t just stop taking the drug and never circle back.” At the same time, he added, “I think it’s important to emphasize metformin’s safety and effectiveness.”
For patients experiencing gastrointestinal side effects, options including switching to extended-release metformin or lowering the dose.
Also, while patients are typically advised to take metformin with food, some experience diarrhea when they do that and prefer to take it at bedtime than with dinner. “If that’s what works for people, that’s what they should do,” Dr. Flory advised.
“It doesn’t take a lot of time to emphasize to patients the safety and this level of flexibility and control they should be able to exercise over how much they take and when. These things should really help.”