Does diabetes modify the effect of FRAX risk factors for predicting major osteoporotic and hip fracture?
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In an observational study population of 62,413 individuals (6,455 [10 %] with diabetes), diabetes was independently associated with major osteoporotic fractures (MOFs) but did not significantly modify the effect of FRAXTM risk factors or prior fracture site. However, the presence of diabetes exerted a much stronger effect on hip fracture risk in younger versus older individuals.
Diabetes mellitus increases fracture risk independent of risk factors that comprise the WHO FRAXTM tool. We explored whether diabetes modifies the effect of FRAX clinical risk factors on MOF and hip fracture risk.
Using a registry of clinical dual-energy X-ray absorptiometry (DXA) results for Manitoba, Canada, we identified women and men aged 40 years and older undergoing baseline DXA in 1996–2011. Health services data were used to identify diabetes diagnosis, FRAX risk factors and incident fractures using previously validated algorithms. Prior fracture was stratified as clinical vertebral, hip, humerus, forearm, pelvis and ‘other’. Cox proportional hazards models were used to test for statistical interactions of diabetes with FRAX clinical risk factors and prior fracture site.
During a mean follow-up of 6 years, there were 4,218 MOF and 1,108 hip fractures. Diabetes was a significant independent risk factor for MOF adjusted for FRAX risk factors including bone mineral density (BMD) (adjusted hazard ratio [aHR] 1.32 [95 % confidence interval (CI) 1.20–1.46]). No significant interactions of FRAX risk factors or prior fracture site with diabetes were identified in analyses of MOF. For predicting hip fractures, age significantly modified the effect of diabetes (aHR age <60, 4.67 [95 % CI 2.76–7.89], age 60–69, 2.68 [1.77–4.04], age 70–79, 1.57 [1.20–2.04], age >80, 1.42 [1. 10–1.99]; pinteraction <0.001).
Diabetes is an independent risk factor for MOFs and does not significantly modify the effect of FRAX risk factors or prior fracture site. However, diabetes exerts a much stronger effect on hip fracture risk in younger than older individuals which needs to be considered in hip fracture prediction.
KeywordsBone mineral density Diabetes Fracture Fracture prediction FRAX Osteoporosis
We are indebted to Manitoba Health for providing data (HIPC File No. 2011/2012—31). The results and conclusions are those of the authors, and no official endorsement by Manitoba Health is intended or should be inferred. This article has been reviewed and approved by the members of the Manitoba Bone Density Program Committee.
Conflicts of interest
SNM is chercheur-boursier des Fonds de Recherche du Québec en Santé. LML is supported by a Manitoba Health Research Chair. SRM holds the Endowed Chair in Patient Health Management (Faculties of Medicine and Dentistry and Pharmacy and Pharmaceutical Sciences, University of Alberta) and receives salary support as a Health Scholar of the Alberta Heritage Foundation for Medical Research and Alberta Innovates-Health Solutions. William Leslie is a speaker bureau (paid to facility) of Amgen, Eli Lilly, and Novartis and has research grants (paid to facility) from Amgen, Genzyme. Suzanne Morin is a consultant to Amgen, Eli Lilly, and Merck and a speaker bureau of Amgen and Eli Lilly and has a research grant from Amgen. Lisa M. Lix and Sumit R. Majumdar declare that they have no conflict of interest.
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