Fracture risk is increased in epilepsy

Abstract

Objectives: To study fracture rates and risk factors for fractures in non-institutionalized patients with epilepsy.

Material and methods: Historical follow-up. Self-administered questionnaires were issued to 755 patients with epilepsy (ICD 10: G40.0 to G40.9) and 1000 randomly selected controls from the background population.

Results: A total of 345 patients (median age: 45, range 17-80 years) and 654 control subjects (median age: 43, range 19-93 years) returned the questionnaire. Before epilepsy was diagnosed there was no difference in overall fracture rate between patients and controls (RR = 1.0, 95% CI: 0.8-1.3). After the diagnosis the overall fracture rate was significantly higher in the patients (RR = 2.0, 95% CI: 1.6-2.5). Fractures of the spine, forearms, femurs, lower legs, and feet and toes were significantly increased. Fractures related to seizures accounted for 33.9% (95% CI: 25.3-43.5%) of all fractures. After elimination of seizure related fractures the increase in fracture frequency was only borderline significant: RR = 1.3 (95% CI: 1.0-1.7, P = 0.042). No difference in fracture energy between patients and controls was observed (low energy fractures: 1.7/1.4%, medium energy fractures: 59.8/52.0%, and high energy fractures: 38.3/46.6%). Use of phenytoin (OR = 2.4, 95% CI: 1.1-5.4) and a family fracture history (OR = 2.4, 95% CI: 1.3-4.6) was associated with an increased fracture risk.

Conclusions: Fractures were more common in epileptics than in controls especially among users of phenytoin. Most of the increase in fracture frequency was related to seizures and not to low bone biomechanical competence.