Incidence of fractures in patients with multiple sclerosis: the Danish National Health Registers

Background: Patients with multiple sclerosis (MS) are potentially at high risk of fracture due to falls and osteoporosis. Objective: To estimate incidence rates of fractures in MS patients, stratified by fracture type, sex and age, and to compare these rates with controls. Methods: The case population consisted of all patients with an accepted diagnosis of MS in the Danish MS Registry (1949–2007). Data were linked to the National Hospital Discharge Register (1977–2007). Patients with MS ( n = 11,157) were 1:6 matched by year of birth, gender, calendar time and region to persons without MS (controls). Incidence rates of fracture were estimated as the number of fractures per 1000 person-years. Incidence rate ratios (IRRs) were calculated by dividing fracture rates in MS patients by fracture rates in controls. Results: Among patients with MS, the incidence rate of any fracture yielded 22.8 per 1000 person-years. The IRR of any fracture between MS patients and controls was 1.40 (95% CI 1.33–1.46). In particular, IRRs of tibia fracture (3.36 [2.75–4.11]), femur fracture (6.66 [5.06–8.76]) and hip fracture (3.20 [2.83–3.62]) were elevated in MS patients versus controls. Conclusion: Fractures occurred more often in patients with MS, especially fractures of the tibia, hip and femur.