Has diabetes control hit a ceiling?

Saeid Shahraz finds a plateau in glucose control among adult diabetes patients in the U.S. from 2007-2014.

April 13, 2018

colorized image of cells under a microscope

In a November 2017 research letter published in JAMA (the Journal of the American Medical Association), scientist Saeid Shahraz, PhD’14, and coauthors described an apparent plateau in glycemic control among adult diabetes patients in the U.S. from 2007-14.

Shahraz notes in the opening line of the letter that over 30 million people in the U.S. had diabetes in 2014. Glycemic control, or blood glucose management, is an essential aspect of diabetes care and is strongly related to vascular complications associated with diabetes, such as loss of eyesight, kidney function, stroke and heart attack. Despite increases in blood glucose testing and awareness during the same period, overall blood glucose control levels (measured by HbA1C) held steady.

Diabetes is a risk factor for other conditions, as well as an outcome of other risk factors, such as obesity. The recommended blood sugar level is under constant debate and may depend on many factors, such as the patient’s age and overall health and disease profile.

For many patients, especially older patients with multiple conditions, the side effects of keeping blood glucose below a strict threshold may generate more discomfort (e.g. hypoglycemia and falls) than is worthwhile. At the same time, younger diabetic patients benefit the most from diabetes management. Previous research, including that done by Shahraz, shows that diabetes control in younger age groups is not as good as that in older age groups.

When asked to speculate on the reasons behind this observed plateau, Shahraz notes that there’s currently not a cogent theory that explains it. “Glycemic control was getting better and better for a long time, but to be fair we don’t know what an amazing level of glycemic control would be. What we discovered here is simply the fact that there has been a plateau. Is it a self-limiting curve? We don’t know. Will it get better with new diabetes interventions over time? We don’t know.”

The study was conducted in partnership with colleagues at Tufts Medical Center and Iowa State University. Coauthor and Associate Dean for Research Cindy Parks Thomas, PhD’00, notes that this paper fits into the larger portfolio of quality of care research conducted at Heller. “Understanding health system quality and the role of social determinants that lead to improved health care and healthier communities is a main focus across many of the Heller research institutes,” she says. “This study provides important new insight into the complex link between patient care and health outcomes across different populations.”

Shahraz’s goal in future studies is to link this phenomenon to mortality data, to show whether patients with poor glycemic control are suffering from higher rates of diabetesrelated mortality. He also hopes to look at the data by subgroups, to see how these trends are playing out for patients of different races or living in different geographic regions.

“We know there are huge disparities by subgroups that may be canceling each other out,” says Shahraz, “but we were looking at the big picture here — and it’s plateaued. We hope this paper triggers thinking around a broad theory that explains this trend.”