People with type 2 diabetes face a higher risk of heart attack, stroke and other diseases involving the heart and blood vessels.
A large Danish study suggests that consistently taking prescribed diabetes medicine over many years could make a meaningful difference to that risk.
Researchers followed nearly 80,000 adults with newly diagnosed type 2 diabetes and examined their prescription-filling patterns for a decade. People who consistently obtained their diabetes medicines remained free from major cardiovascular problems for more than seven months longer, on average, than people whose medication use stayed low.
Type 2 diabetes develops when the body cannot use insulin effectively or cannot produce enough insulin to keep blood sugar within a healthy range. Over time, high blood sugar can damage blood vessels and nerves, increasing the risk of heart disease, stroke, kidney disease and other complications.
Medicines that lower blood sugar are therefore an important part of treatment for many patients. But receiving a prescription does not necessarily mean that a person will continue taking the medicine as recommended for years.
There are many reasons people may stop or irregularly take long-term medicine. Side effects, complicated routines, cost, other illnesses, work and family demands, or simply feeling well despite having diabetes can all affect medication use.
Researchers from the University of Copenhagen and their collaborators wanted to understand how these long-term patterns were connected with cardiovascular health. They used Denmark’s national health registries, which allowed them to study pharmacy and health records without relying on people to remember and report their own medication habits.
The study included 79,510 adults who were newly diagnosed with type 2 diabetes and began non-insulin diabetes medicine between 2005 and 2012. Researchers then examined monthly pharmacy records over a period of up to 10 years.
Three broad patterns appeared. About 41% of patients maintained high adherence, meaning they consistently filled their prescriptions, while 33% had a moderate pattern and 26% showed an early drop followed by persistently low adherence.
The differences in heart health were notable. People in the low-adherence group had a 27% higher rate of major cardiovascular events compared with those who consistently obtained their medicine.
Even people in the middle group had a 7% higher rate of cardiovascular events than the high-adherence group. This suggests that the relationship was not limited to people who almost completely stopped obtaining their treatment.
The strongest association involved ischemic heart disease, which develops when the heart does not receive enough oxygen-rich blood, usually because arteries have become narrowed or blocked. Low adherence was associated with a 45% higher rate of this form of heart disease and a 24% higher rate of stroke.
The results were particularly striking among younger adults. Low adherence was linked to a 73% higher rate of experiencing a cardiovascular event before age 55 compared with consistent medication use.
This could be especially important because people who develop type 2 diabetes at a younger age may live with the disease for many decades. That gives high blood sugar and other cardiovascular risks more time to cause damage.
The researchers also found that medication habits were connected with people’s wider circumstances. Those with low adherence were more likely to live alone, have lower incomes and have additional long-term health conditions.
These findings suggest that missing medicine is not always a simple matter of forgetting. Some patients may be dealing with practical, financial, medical or social difficulties that make a daily treatment plan harder to maintain.
The researchers adjusted their analysis for a range of these differences, and lower adherence remained associated with greater cardiovascular risk. However, because the research was observational, it cannot prove that inconsistent medication use directly caused the additional heart attacks or strokes.
The study was published in The Lancet Regional Health – Europe. It was led by Associate Professor Jordi Merino and included researchers from the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen.
A major strength of the research is its size and long follow-up, as well as its use of national pharmacy records rather than memory-based surveys. Still, filling a prescription does not prove that every dose was actually taken, and people who consistently collect medicines may also follow other healthy behaviors that contribute to better outcomes.
The study also examined a broad group of non-insulin diabetes medicines rather than showing that every individual drug produces the same benefit. Treatment decisions therefore still need to be personalized according to a patient’s health, age, other medicines and risk factors.
Overall, the results reinforce an important point about chronic disease care: choosing an effective medicine is only part of the job. Helping people continue treatment over the long term—and identifying the real reasons when they cannot—may be an important way to protect both blood sugar control and cardiovascular health.
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Source: University of Copenhagen.
