A single percentage increase in the level of hemoglobin A1c (HbA1c) in patients with newly diagnosed type 1 diabetes is significantly associated with an increase in fracture risk, according to findings in a study published in Diabetic Medicine.

To determine the effect of glycemic control on fracture risk, Rasiah Thayakaran, PhD, of the University of Birmingham (England) and colleagues analyzed data from 5,368 patients with newly diagnosed type 1 diabetes in the United Kingdom. HbA1c measurements were collected until either fracture or the end of the study, and were then converted from percentages to mmol/mol. Patient age ranged between 1 and 60 years, and the mean age was 22 years.

During 37,830 person‐years of follow‐up, 525 fractures were observed, with an incidence rate of 14 per 1,000 person‐years. The rate among men was 15 per 1,000 person‐years, compared with 12 per 1,000 person‐years among women. There was a significant association between hemoglobin level and risk of fractures (adjusted hazard ratio, 1.007 mmol/mol; 95% confidence interval, 1.002-1.011 mmol/mol), representing an increase of 7% in risk for fracture for each percentage increase in hemoglobin level.

“When assessing an individual with newly diagnosed type 1 diabetes and high HbA1c, increased clinical awareness about the fracture risk may be incorporated in decision‐making regarding the clinical management and even in prompting early antiosteoporotic intervention,” Dr. Thayakaran and coauthors wrote.

The researchers acknowledged the study’s limitations, including a possibility of residual confounding because of their use of observational data. In addition, they could not confirm whether the increase in fracture risk should be attributed to bone fragility or to increased risk of falls. Finally, though they noted using a comprehensive list of codes to identify fractures, they could not verify “completeness of recording ... and therefore reported overall fracture incidence should be interpreted with caution.”

The study was not funded. The authors reported no conflicts of interest.

SOURCE: Thayakaran R et al. Diab Med. 2019 Mar 8. doi: 10.1111/dme.13945.