Low hemoglobin A1c (HbA1c) and low body mass index (BMI) are associated with higher risk for bone fracture in individuals with type 2 diabetes (T2D) aged ≥50 years, according to the results of a study published in the Journal of Diabetes and Its Complications.
Individuals with T2D are at greater risk for bone fracture, but studies investigating the role of HbA1c, BMI, acute complications, and diabetes medications in fracture risk have yielded inconsistent results.
To better understand the role of these various factors on increased fracture risk in individuals with T2D, data from 354,108 individuals in the multicenter diabetes patient registry (DPV) in Germany were analyzed. Individuals aged ≥50 years were included, and those who had experienced a fracture in the previous 12 months were allocated to the fracture group.
Of the 354,108 individuals, 4821 had experienced a fracture in the preceding 12 months. Individuals who had a recent fracture were more often women (62.7% vs 47.4% in the control group), were older, and had a longer diabetes duration, lower BMI, and lower HbA1c than individuals who had never experienced a fracture. Low HbA1c was associated with higher risk for fracture at the hip (P <.001), spine (P <.05), and lower limb (P <.01) in women but only at the hip (P <.002) and lower limb (P <.001) in men. BMI was inversely related to risk for fracture at the hip (P <.001) and spine (P =.014) in women and at the hip (P <.001) in men, whereas higher BMI was associated with an increased risk for lower limb fractures in men (P =.004).
The use of sodium-glucose cotransporter 2 inhibitors (SGLT2is) and lifestyle therapy was associated with the highest fracture risk in the overall cohort compared with other diabetes treatments (P <.05). The researchers also noted that occurrence of >1 diabetic ketoacidosis event or hypoglycemic coma was linked to increased fracture risk in the overall population.
Taken together, these findings contradict previous indications that poor glycemic control is related to fracture risk, potentially because of the cross-sectional nature of the current study, which prevented the evaluation of long-term effects of elevated HbA1c levels. The inverse relationship between BMI and risk for fracture at the hip and spine may be related to the lack of protective fatty deposits in these areas, whereas the association of higher BMI and lower limb fractures may be due to the lack of distribution of protective fatty deposits on the legs in combination with the increased impact of the fall in individuals with obesity.
In addition to these findings regarding BMI and HbA1c, the investigators concluded that “SGLT2i treatment might be detrimental, at least in female patients. Even if DKA is rare in [patients with T2D], it seems to be related to fractures and because the DKA rate increased…during the last decades, this is an important topic for further research.”
Eckert A, Mader JK, Altmeier M, et al. Fracture risk in patients with type 2 diabetes aged ≥50 years related to HbA1c, acute complications, BMI and SGLT2i-use in the DPV registry [published online June 27, 2020]. J Diabetes Complicat. doi:10.1016/j.jdiacomp.2020.107664