Abstracts

Children and adults with epilepsy experience poor bone mineralization. This mineralization deficit appears to increase with longer duration of epilepsy and/or its treatment. The effect of antiepileptic drug (AED) initial monotherapy compared to polytherapy on bone mineralization has not been examined previously. We determined BMD in children treated with monotherapy (only ever exposed to carbamazepine (CBZ), valpraote (VPA) or lamotrigine (LTG) compared with AED polytherapy and to healthy controls., Age-normalized z-score total body BMD (Lunar[reg]) was compared in patients 6-18 years treated for epilepsy with initial monotherapy with VPA, CBZ or LTG were compared with those patients receiving polytherapy and healthy controls.
General exclusion criteria for patients included being non-ambulatory, treated for co-morbid disease or consuming known bone-adverse medications. Exclusions from the monotherapy group included exposure to an AED other than initial and ongoing monotherapy with either VPA, CBZ or LTG. Activity and calcium intake were examined. Statistical analysis included ANOVA and student t-test., 33 patients (13[underline]+[/underline]3y; 13f, 20m) treated with monotherapy (CBZ=13, VPA=15, LTG=4) were compared to 40 patients (11.7[underline]+[/underline]3.5y; 27f, 13m) recieving AED polytherapy and 36 healthy controls (13[underline]+[/underline]2y.6yr; 22f, 14m). Age, height and weight were not statistically different between groups.
Duration of epilepsy for the monotherapy group was 5.2y (CI=4, 6.4)compared to 6.3y (CI=5,7.7).
Age mean z-scores for total BMD was (0.5[underline]+[/underline].17) for patients recieving monotherapy and was similar to controls (0.5[underline]+[/underline].15). However, patients receiving AED polytherapy had lower BMD (-0.04[underline]+[/underline].15) than for patients recieving AED monotherapy or for controls, p[lt]0.02., AED Polytherapy was associated with significant reduction in BMD compared to patients recieving AED monotherapy. This reduction was far greater than the non-statistical trend towards the slightly longer treatment duration of polytherapy patients compared to monotherapy patients. Furthermore, while patients recieving AED monotherapy had similar BMD compared to controls, patients recieving AED polytherapy experienced a significant osteopenia when compared to controls. With larger number of patients the specific effect of inidvidual AED on bone health should become apparent., (Supported by Investigator initiated grant from GSK.)