Comparison of Methods for Improving Fracture Risk Assessment in Diabetes: The Manitoba BMD Registry

Abstract

Type 2 diabetes is a risk factor for fracture independent of FRAX (fracture risk assessment) probability. We directly compared four proposed methods to improve the performance of FRAX for type 2 diabetes by: (1) including the rheumatoid arthritis (RA) input to FRAX; (2) making a trabecular bone score (TBS) adjustment to FRAX; (3) reducing the femoral neck T-score input to FRAX by 0.5 SD; and (4) increasing the age input to FRAX by 10 years. We examined major osteoporotic fractures (MOFs) and hip fractures (HFs) over a mean of 8.3 years observation among 44,543 women and men 40 years of age or older (4136 with diabetes) with baseline lumbar spine and hip DXA from 1999 through 2016. Controlled for unadjusted FRAX probability, diabetes was associated with an increased risk for MOFs and HFs. All four FRAX adjustments attenuated the effect of diabetes, but a residual effect of diabetes was seen on MOF risk after TBS adjustment, and on HF risk after the RA and TBS adjustments. Among those with diabetes, unadjusted FRAX risk underestimated MOF (observed/predicted ratio 1.15; 95% CI, 1.03 to 1.28), but this was no longer significant after applying the diabetes adjustments. HF risk was more severely underestimated (observed/predicted ratio 1.85; 95% CI, 1.51 to 2.20) and was only partially corrected with the diabetes adjustments (still significant for the RA and TBS adjustments). Among those with diabetes, there was moderate reclassification based upon a fixed MOF cut-off of 20% (4.1% to 7.1%) or fixed HF cut-off of 3% (5.7% to 16.5%). Net reclassification improvement increased for MOF with each of the diabetes adjustments (range 3.9% to 5.6% in the diabetes subgroup). In conclusion, each of the proposed methods for addressing limitations in the ability of FRAX to assess fracture risk in individuals with diabetes was found to improve performance, though no single method was optimal in all settings. © 2018 American Society for Bone and Mineral Research.

Assessment of bone quality with trabecular bone score in type 2 diabetes mellitus: A study from the FRISBEE cohort

“…In a large study assessing TBS in a cohort of 29 407 postmenopausal women (all over 50 years, mean age 65.4 years) Hans et al reported 1668 incident major osteoporotic fractures after 5 years of follow‐up. The occurrence of fractures was predicted equally well by lumbar spine BMD and by TBS, but the association of both parameters performed better than either separately …”

“…Currently, the University of Sheffield Fracture Risk Assessment tool (FRAX) developed to calculate the 10-year probability of a major fracture (clinical spine, humerus, wrist fracture, hip) or hip fracture alone, based on validated clinical risk factors (CRFs) independent of BMD, does not include several causes of secondary osteoporosis, notably diabetes, as a primary entry variable, and therefore underestimates fracture risk in T2D. 3,7 Non-invasive bone quality-related markers are needed to identify patients with T2D at risk for fracture.…”

Glycemic Control and Insulin Treatment Alter Fracture Risk in Older Men With Type 2 Diabetes Mellitus

“…Also, a number of modifications to fracture risk assessment have been proposed for this population. However, such modifications are largely based on presence or absence of diabetes and do not identify those with diabetes at greatest risk and therefore should be screened . We had previously shown significant fracture risk among older adults with diabetes, mediated by peripheral neuropathy and cardiovascular disease such as congestive heart failure .…”

Management of fracture risk in patients with diabetes—Chinese Expert Consensus

“…However, the FRAX tool underestimates the fracture risk in T2D patients . Combining the FRAX score with the TBS, or substituting diabetes for rheumatoid arthritis, or reducing the BMD T‐score by 0.5, or adding 10 years to age in the FRAX tool helps improve the accuracy of predicting the fracture risk in T2D patients, but none of these approaches has been shown to be better than the others in all settings . It should also be pointed out, changes in the FRAX score parallel fracture rates in people with diabetes …”