Patients with type 2 diabetes and poor glycemic control or severe hypoglycemia may be at greater risk for fracture, according to recent research from a Japanese cohort of older men and postmenopausal women.
“The impacts of severe hypoglycemia and poor glycemic control on fractures appeared to be independent,” noted Yuji Komorita, MD, PhD, of the department of medicine and clinical science, Graduate School of Medical Sciences at Kyushu University, and colleagues. “This study suggests that the glycemic target to prevent fractures may be HbA1c <75 mmol/mol, which is far higher than that used to prevent microvascular complications, and higher than that for older adults with type 2 diabetes.”
Dr. Komorita and colleagues performed a prospective analysis of fracture incidence for 2,755 men and 1,951 postmenopausal women with type 2 diabetes in the Fukuoka Diabetes Registry who were mean 66 years old between April 2008 and October 2010. At the start of the study, the researchers assessed patient diabetes duration, previous fracture history, physical activity, alcohol and smoking status, whether patients were treated for diabetic retinopathy with laser photocoagulation, and their history of coronary artery disease or stroke. Patients were followed for a median 5.3 years, during which fractures were assessed through an annual self-administered questionnaire, with the results stratified by glycemic control and hypoglycemia.
Overall, there were 249 men and 413 women who experienced fractures during the study period, with a follow-up rate of 97.6%. In a multivariate analysis, patients with a higher risk of fracture included those with two or more episodes of severe hypoglycemia (hazard ratio, 2.25; 95% confidence interval, 1.57-3.22) and one episode of severe hypoglycemia (HR, 1.57; 95% CI, 1.11-2.20). In patients without severe hypoglycemic episodes, there was an increased risk of fracture in those with baseline hemoglobin A1c (HbA1c) level of 53 to less than 64 mmol/mol (7% to less than 8%; HR, 1.14; 0.94-1.39), 64 to less than 75 mmol/mol (8% to less than 9%; HR, 1.11; 95% CI, 0.86-1.43), and at least 75 mmol/mol (at least 9%; HR, 1.45; 95% CI, 1.06-1.98).
Compared with postmenopausal women, the unadjusted risk of fracture was higher in men with multiple severe hypoglycemic episodes (HR, 3.46; 95% CI, 2.05-5.85) and one episode of hypoglycemia (HR, 2.81; 95% CI, 1.74-4.56). These higher risks in older men persisted after adjustment for age, multivariate factors, and HbA1c.
“The association between severe hypoglycemia, poor glycemic control, and fracture risk at any anatomic site seems to be stronger in men than in postmenopausal women, although the interaction between men and postmenopausal women for fracture risk was not significant,” the researchers said. “The higher incidence rate of fractures in postmenopausal women, compared with men, was attributed to drastic changes in sex hormones after menopause, which may reduce the apparent impacts of hyperglycemia and severe hypoglycemia on postmenopausal women.”
Researchers said they did not consider potential external factors for fracture incidence, nor did they measure incident falls or other markers of bone health, such as bone mineral density and 25-hydroxyvitamin D levels. They also noted among the limitations of the study the self-reported nature of fracture reporting, and the lack of generalizability of the results.
This study was funded in part by grants from The Japan Society for the Promotion of Science KAKENHI from the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Junior Scientist Development Grant supported by the Japan Diabetes Society; and the Lilly Research Grant Program for Bone & Mineral Research. The authors reported no relevant conflicts of interest.
SOURCE: Komorita Y et al. Diabet Med. 2019 Sep 25. .