Race affects medication adherence

African Americans may be less likely than whites to take their medication for Type 2 diabetes as it is prescribed, a new study suggests.

The researchers found that adherence rates were as much as 12 percent lower among black people when compared to whites.

“That's an unacceptable difference, particularly because African Americans tend to have higher rates of diabetes and disease-related complications,” said Rajesh Balkrishnan, a study co-author and the Merrell Dow professor of pharmacy at Ohio State University.

Each of the nearly 2,700 study participants were covered by Medicaid, which provided prescription medication coverage to all enrollees. Still, more than a third of the African Americans and whites in this study failed to take their anti-diabetic medications properly.

“Adherence rates for these types of medications should be better than 90 percent, regardless of who takes them,” Balkrishnan said. “Such low rates of adherence may be related to lower socioeconomic status and to lower levels of education.

“Many commercial insurers pay for educators to teach patients the importance of taking their medications as prescribed,” he continued. “Medicaid needs to do the same thing. While it invests a lot of money in providing services, it does little to educate its recipients about those services and how to use them. People need to understand the importance of taking their medications.”

The results appear in a recent issue of the Journal of the National Medical Association.

The researchers gathered two years' worth of patient information from the North Carolina Medicaid program database. They culled the database for adults with Type 2, or insulin resistant, diabetes, and found 1,527 black and 1,128 white people who fit the criteria.

The information gathered was solely from patients who were taking one of three types medications commonly used to treat diabetes – a thiazolidinedione (TZD), a sulfonylurea or metformin.

The researchers determined individual medication adherence rates by calculating how often each person refilled his prescription. They assumed that a prescription filled meant that the previous prescription had been taken.

Based on this calculation alone, the researchers found that the African American diabetic patients in this Medicaid population took their medication as prescribed 54 percent of the time, compared to white diabetic patients who took their medication as prescribed 59 percent of the time.

The researchers also found that, regardless of race, people who took the anti-diabetic drug metformin were 62 percent less likely to take the medication as prescribed.

Other studies have suggested that metformin alone is ineffective at controlling the symptoms of diabetes. Balkrishnan said that most of the patients who took metformin in this study ultimately started to take another anti-diabetic drug, either alone or in combination with metformin.

Balkrishnan conducted the study with Ohio State colleague Rahul Shenolikar, and with researchers from the Wake Forest University School of Medicine and the North Carolina State Center for Health Statistics.