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One in three patients with type 2 diabetes fail to take medication

One-third of patients with type 2 diabetes prescribed metformin do not take their recommended doses, possibly because of adverse events related to the medication, according to findings published in Diabetes, Obesity and Metabolism.

“Nonadherence and nonpersistence with medications in type 2 diabetes are associated with worse outcomes, including poorer glycemic control, more complications and higher overall costs,” Andrew McGovern, BMBS, from the University of Surrey, England, and colleagues wrote. “Despite these adverse outcomes, a substantial proportion people with type 2 diabetes do not take their medications as prescribed.”

McGovern and colleagues conducted a meta-analysis and systematic review to investigate the likelihood of patients with type 2 diabetes adhering to their medications.

The researchers identified and analyzed 48 observational and interventional studies that compared the adherence or persistence rates among different medications for the treatment of hyperglycemia among patients with type 2 diabetes (n = 1,696,939). For studies that compared the same medications, they performed a random effects meta-analysis to determine the mean difference, OR or HR of the pooled outcomes.

Results showed that adherence rates were lowest among patients who took metformin, with 30% of prescriptions not being taken. Patients taking DPP4 inhibitors, or gliptins, were most likely to adhere to their medication, with only 10% to 20% of prescriptions not being taken. A total of 23% of sulfonylureas, such as gliclazide, and 20% of thiazolidinediones, such as pioglitazone, that were prescribed to patients were not taken.

The likelihood of discontinuing medication was doubled among patients taking GLP1 receptor agonists, such as exenatide, compared with those taking insulin.

The researchers suspect that lower adherence to certain medications is due to their adverse events, noting that metformin often causes gastrointestinal disturbance, while DPP4 inhibitors are generally well tolerated. They noted that multiple daily dosing may also contribute to adherence differences.

“The importance of diabetes patients taking their prescribed medication cannot be underestimated,” McGovern said in a press release. “A failure to do so can lead to complications in their condition including eye disease and kidney damage... What this latest research suggests is that patients find some of these medication classes much easier to take than others.”

“Fortunately for type 2 diabetes, we have lots of treatment options and switching to a different medication class which is easier to take could provide an easy way to improve adherence,” he added. “I would also encourage doctors and nurses to actively ask their patients about medication adherence.” – by Alaina Tedesco

Disclosure: McGovern reports receiving research funding from AstraZeneca and Eli Lilly and Company. Please see study for all other authors’ relevant financial disclosures.