Fracture risk and treatment thresholds in patients with diabetes

Aims: Traditional risk factors underestimate fracture risk in individuals with diabetes. In this population-based case-control study we aimed to determine T-score thresholds for type 1 and 2 diabetes (T1D and T2D) with equivalent risk of fractures as that of individuals without diabetes and a T-score of -2.5. Research Design and Methods: We collected dual energy x-ray absorptiometry (DXA) data (2000–2019), information on diagnoses (1977–2019) and redeemed medications (1997–2019) from the National Danish Registries which are linked by a unique identifier. Cases were individuals with the first incident major osteoporotic fracture (MOF) within two years before or one year after a DXA and controls were fracture free and matched on age, gender, and time period of the DXA. Logistic regression modelling was used in the case-control analysis. Results: We identified 17,703 cases and 17,703 controls. T1D and T2D were associated with an increased risk of MOF (odds ratio: 1.8, 95 % CI:1.4;2.3 and 1.2, 95 % CI:1.1;1.3, respectively) adjusted for hip BMD. T1D and T2D patients had a similar risk of MOF at T-scores (total hip) = -1.4 and -2.1, respectively, as patients without diabetes with a T-score of -2.5. For hip fracture, the equivalent risk was correspondingly reached with T-scores of -1.9 and -1.6. Similar findings apply for femoral neck and lumbar spine BMD. Conclusions: Compared to individuals without diabetes, fracture risk was increased in patients with T1D and T2D independent of BMD. Our study suggests that the T-score thresholds for treatment initiation in T1D and T2D should be increased.