title: Epilepsy: fractures and the role of cumulative antiepileptic drug load.
abstract: BACKGROUND
  An association between antiepileptic drugs (AEDs), low bone mineral density (BMD), fractures, and abnormalities in bone metabolism has been suggested for a longer period, although conclusive evidence has not been reported. We aimed at studying patient characteristics in a high-risk population.
  
  
  METHODS
  All adult patients from a residential unit of a tertiary epilepsy center who were diagnosed with osteoporosis and consequently treated with a bisphosphonate at that moment were included. Correlations between reported fractures and patient characteristics were explored.
  
  
  RESULTS
  Of the total population of 261 adult patients, 54 patients were included resulting in a high prevalence rate of 21% osteoporosis in this population. The number of fractures correlated significantly with ambulatory status (r = -0.269, P = 0.05), drug load (r = 0.286, P = 0.04), and current number of AEDs (r = 0.283, P = 0.04). Correlations could not be provided for individual drugs in our population as only a minority was on monotherapy and even less patients had always been on monotherapy of the same antiepileptic drug. Linear regression analysis showed that cumulative drug load (defined by a surrogate parameter: the total duration of epilepsy multiplied by the number of AEDs) was the dominant factor explaining the occurrence of fractures.
  
  
  CONCLUSIONS
  In this high-risk population, we obtained a positive and strong correlation between the occurrence of fractures in a diagnosed population with osteoporosis and the cumulative drug load of AEDs. This effect seems general, independent of the type of AEDs that were used.
authors: Department of Neurology, Maastricht University Medical Center, the Netherlands. k.beerhorst@atriummc.nl
authors: K
authors: K
authors: Beerhorst
authors: F M
authors: FM
authors: Schouwenaars
authors: I Y
authors: IY
authors: Tan
authors: A P
authors: AP
authors: Aldenkamp
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D015519:Bone Density / Q000187:drug effects*; D004827:Epilepsy / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000139:chemically induced* / Q000150:complications; D058866:Osteoporotic Fractures / Q000139:chemically induced* / Q000150:complications
chemical_list: D000927:Anticonvulsants