Basel, Switzerland—There is a higher risk of fragility bone fracture for people with diabetes, and a new study was able to identify a key factor specific to type 1 diabetes (T1D) patients.

The study in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism reports that poor glucose control significantly reduces the risk, in T1D patients, of a fall from standing height or less that results in a broken bone.

“We investigated the association between the degree of glycemic control and fracture risk by using a large cohort of newly diagnosed type 1 and type 2 diabetes patients,” explained study author Janina Vavanikunnel, MD, of the University Hospital Basel in Basel, Switzerland. “Both types of diabetes are associated with fragility fractures and we showed that poor glycemic control is associated with an increased risk of fracture in type 1 diabetes.”

Researchers used a primary care database from the United Kingdom for a nested case-control study within a cohort of 3,329 patients with T1D and 44,275 patients with type 2 diabetes (T2D). What was unusual about the study was that it focused on a 3-year average of hemoglobin A1c values instead of short-term measurements. Participants had an average of nine A1c measurements if they had T1D and 11 if they had T2D.

This study found that poor glycemic control—defined as an A1c level above 8%—is associated with an increased risk of fractures in patients with T1D but not T2D, at least in short-term disease.

The authors suggest that the risk of fracture in patients with T2D might be because of factors beyond glycemic control, such as comorbidities or medication. “Nevertheless, fracture risk in type 2 diabetes is of clinical relevance as well as it is a major health concern worldwide due to its high prevalence,” added coauthor Sarah Charlier, MSc, of University Hospital Basel.

The study, which included researchers from Boston University School of Medicine in Lexington, Massachusetts, focused on patients whose T1D or T2D was newly diagnosed between 1995 and 2015. Results indicate that median duration between diabetes onset and fracture date was 4.5 years for both types of diabetes.

Researchers report that the risk of fracture was increased in T1D patients with mean HbA1c >8.0% (aOR 1.39, 95% CI, 1.06-1.83) compared with T1D patients having mean HbA1c values less than 7%. While no such effect was detected in T2D patients, their risk of fracture also was elevated, most notably with current use of rosiglitazone and pioglitazone.

“The impact of glycemic control on the risk of low-trauma fracture differs between T1DM and T2DM patients,” study authors conclude. “Poor glycemic control increased the risk of fracture in T1DM but not in T2DM patients.”

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