Abstracts

The incidence of fractures among patients with epilepsy has never been studied in a large, population-based primary-care database. The objective of this study was to assess and compare the incidence of fractures among epilepsy patients and non-epileptic control patients. This study of a UK-based primary-care database covered a period from 1990-1998. Patients were included in the epilepsy cohort if there was sufficient evidence of active epilepsy, as indicated by either medical diagnoses or the use of antiepileptic drugs (AEDs) after the start of the General Practice Research Database (GPRD) follow-up of the practice. The control cohort comprised randomly selected patients from the GPRD without epilepsy. Two control patients were matched to each epilepsy patient by practice and index date. Study outcomes were occurences of fractures during follow-up. Fractures were identified through relevant Oxford Medical Information System (OXMIS) and Read codes. Incidence rates were calculated by dividing the number of fractures by the total number of person-years. Poisson regression analysis was used to estimate age and gender adjusted incidence density ratios (IDRs). The study population comprised 40,485 and 80,970 patients in the epilepsy and control cohort, respectively. The median duration of follow-up was about 3 years. The median age was higher in the epilepsy cohort (39.1 vs. 34.1 years), while the gender distribution was similar. In the epilepsy cohort, 3,489 fractures occurred during 143,754 person-years of follow-up, yielding an overall incidence rate of 241.9 per 10,000 person-years. This rate was about double the incidence rate of the control cohort: crude IDR 1.96 (95% CI: 1.87-2.05). The IDR decreased slightly to 1.89 (1.81-1.98) after adjustment for age and gender. When comparing IDRs among the different groups of fractures, the highest risk estimate was found for hip and femur fractures (adjusted IDR 2.79, 95% CI: 2.41-3.24). The IDRs for hand/arm, lower leg/foot and other fractures were 1.70 (95% CI: 1.57- 1.84), 1.89 (95% CI: 1.70-2.10) and 1.94 (95% CI: 1.80-2.09), respectively. The risk of a fracture was nearly twice as high among patients with active epilepsy compared to the general population in this population-based study in a UK-based primary-care setting. The fracture risk was highest for hip and femur. (Supported by GlaxoSmithKline)