The Fracture Risk Assessment Score (FRAX) algorithm may underestimate the risk for fracture in patients with type 2 diabetes (T2D), according to findings published in Acta Diabetologica.
Patients with T2D have higher bone mineral density (BMD) than those without diabetes, but have a significantly greater risk for fractures. This seeming contradiction between a higher BMD and an increased risk for fractures has led to hypotheses that patients with T2D may have impaired bone quality that reduces bone strength.
Researchers conducted a retrospective study to confirm the relationship between the degree of metabolic compensation, as expressed by HbA1c, and the 10-year probability of experiencing a major fracture or hip osteoporotic fracture, using the FRAX algorithm.
The cohort comprised 6355 individuals aged 50 years and older who were evaluated for osteoporosis at a single clinic. HbA1c levels were available for 242 individuals, and all underwent a dual-energy X-ray absorption (DEXA) scan of the lumbar spine and femoral neck.
Compared with those without diabetes, patients with T2D had higher BMD and T-scores of the femoral neck (average BMD, 0.71 ± 0.13 vs 0.65 ± 0.12 g/cm2 [P =.0003]; average T-score, −1.54 ± 1.09 vs −2.14 ± 0.93 [P <.0001]). Patients with T2D had a FRAX score that was significantly lower vs in patients without diabetes for both major osteoporotic fractures and hip fractures. The FRAX score, which was calculated for major osteoporotic and hip fractures, strongly correlated with HbA1c.
“A prospective multicentric study, taking into account the real incidence of fractures during a follow-up period of at least 10 years in a larger population consisting of [patients with T2D] and non-diabetic subjects is needed to assess whether the HbA1c-corrected FRAX may reliably predict fracture risk in subjects with [T2D],” wrote the authors.
Valentini A, Cianfarani MA, De Meo L, et al. FRAX tool in type 2 diabetic subjects: the use of HbA(1c) in estimating fracture risk [published online July 6, 2018]. Acta Diabetol. doi: 10.1007/s00592-018-1187-y