Site-specific fracture incidence rates among patients with type 1 diabetes, type 2 diabetes or without diabetes in Denmark (1997-2017)
Objective: To investigate trends of incidence rates at different fracture sites for patients with type 1 diabetes and type 2 diabetes compared to patients without diabetes in Denmark in 1997-2017.
Research Design and Methods: Patients aged 18+ with a vertebral, hip, humerus, forearm, foot, or ankle fracture between 1997 and 2017 were identified from Danish hospital discharge data. Incidence rates (IRs) per 10,000 person years were calculated over the study period. Median IRs for the first (1997-2001) and the last (2013-2017) five years were compared. We estimated age-adjusted IR ratios (IRRs) of fractures among patients with type 1 and type 2 diabetes to patients without diabetes, using Poisson models.
Results: Except for foot fractures, fracture IRs were higher in patients with type 1 or 2 diabetes compared to patients without diabetes. Hip fracture IRs declined between the first and last five years by 35.2%, 47.0% and 23.4% among patients with type 1 diabetes, type 2 diabetes, and patients without diabetes, respectively. By contrast, vertebral fracture IRs increased 14.8%, 18.5%, 38.9% in patients with type 1 diabetes, type 2 diabetes and patients without diabetes, respectively. While age-adjusted IRRs remained elevated in patients with type 1 diabetes compared to patients without diabetes, IRRs in patients with type 2 diabetes converged with those observed in patients without diabetes.
Conclusion: Unadjusted fracture rates are higher in patients with diabetes but have decreased between 1997 and 2017 except for vertebral fractures that increased in all groups. Fracture rates change after age-adjustment.