(Reuters) — The number of U.S. diabetics with healthy blood sugar levels has declined in recent years, a study suggests.
Researchers analyzed data on 1.6 million adults with diabetes from 2006 to 2013. During this period, the proportion with HbA1c below 7% declined from 56% to 54%, and the share with HbA1c at or above 9% rose from 10% to 12%.
“Clearly, there is a sizable proportion of patients with poor glycemic control – and many of them are young,” said lead author Kasia Lipska of Yale University. “We need to do better for them.”
The researchers examined data on prescriptions and blood sugar test results to see how changes in medication utilization might relate to shifts in the proportion of diabetics with healthy blood sugar.
Use of thiazolidinediones plummeted from 2006 to 2013 when 1 drug in this class (rosiglitazone) was linked to an increased risk of heart attack, stroke and congestive heart failure. Thiazolidinedione prescriptions accounted for less than 6% of the market share for diabetes drugs by the end of the study period, down from 29% at the start.
Prescriptions also fell for sulfonylureas. These medicines accounted for 31% of prescriptions at the end of the study, down from 39%.
Meanwhile, DPP-4 inhibitors, introduced around the start of the study period, accounted for 15% of prescriptions by 2013. (These drugs include sitagliptin, saxagliptin and vildagliptin, for example.)
Prescriptions for metformin rose from 48% to 54% over the course of the study.
The study didn’t explore why shifts in drug utilization or changes in glycemic control occurred, but it’s possible at least some patients were using less effective medicines by the end of the study, Lipska said by email.
“Many of the newer medications have the advantages of not causing weight gain or hypoglycemia, however, some are not as potent in lowering blood sugar levels as many of the older medications,” Lipska said. “In addition, just because medications are available and put into use doesn’t mean that they are necessarily applied in ways that improve care.”
One limitation of the study is its focus on people with private insurance or Medicare who may be more likely to take expensive newer medicines than uninsured patients, the authors note in Diabetes Care, online Sept. 22.
Another drawback is that researchers only had blood sugar data for about 25% of the people in the study, noted Dr. David Nathan, director of the Mass. General Hospital Diabetes Center in Boston.
“Other data have suggested a major improvement in diabetes control over the past 20 years,” Nathan, who wasn’t involved in the study, said by email.
Recently, however, despite the introduction of new drugs, improvement in blood sugar control has leveled out, Nathan said.
“The new medicines are substantially more expensive without obvious benefits,” he said.
With so many drugs to choose from, it’s also possible people are overlooking the role of diet and exercise in managing the disease, noted Dr. William Herman, a researcher at the University of Michigan in Ann Arbor who also wasn’t involved in the study.
“Obesity and lack of focus on diet and physical activity may certainly be contributing to the lack of improvement in blood sugar control,” Herman said by email.