The risk of fracture in patients with incident multiple sclerosis patients in Denmark

Background: Patients with multiple sclerosis (MS) may be at increased risk of fractures owing to osteoporosis and falling. Objective: To evaluate the risk of fracture in incident MS patients from a dedicated registry, and population-based controls. Methods: We conducted a population-based cohort study (1996-2007) utilising the Danish National Health Registers that were linked to the Danish MS Registry, and the Danish MS Treatment Registry. Incidence of MS patients (2963 cases) were 1:6 matched by year of birth, gender, calendar time and region to persons without MS (controls). Cox proportional hazards models and logistic regression were used to estimate risk of fracture in MS. Time-dependent adjustments were made for age, history of diseases and drug use. Results: Compared with controls, patients with MS had no overall increased risk of fracture: adjusted Hazard Ratio (adj. HR) 1.0 [95% CI 0.9-1.2]. However, the risk of femur/hip fracture (adj. HR 1.9 [1.1-3.4]) was significantly increased versus controls. As compared with unexposed patients, MS patients who had been exposed to a short-course of methylprednisolone in the prior year had no significantly increased risk of osteoporotic fracture: adj. HR 1.2 [0.5-2.9]. Disabled MS patients (with expanded disability status scale [EDSS] from 6 to 10) had a 2.6-fold increased risk of osteoporotic fracture (adj. Odds Ratio 2.6 [1.0-6.6]) versus patients with low EDSS (0-3). Conclusion: Patients with MS had a higher risk of femur/hip fracture than controls. Disability status is probably more important than glucocorticoid use in the aetiology of MS and osteoporotic fracture.