Abstract

Objective: To determine whether the efficacy and tolerability of adjunctive lamotrigine differ as a function of whether persons with mental retardation and refractory epilepsy resided in institutions or the community.Research design and methods: The analysis was retrospective and employed data from a previously published, open-label study. To be eligible for enrollment, patients needed to be receiving stable regimens of up to three antiepileptic medications at enrollment and to have experienced at least two seizures per month in the 3 months prior to enrollment. The study included an Escalation Phase during which lamotrigine was titrated to a target dose, an 8‐week Maintenance Phase during which doses of lamotrigine and concomitant antiepileptic drugs were maintained, and a 12‐week Optimization Phase during which doses of antiepileptic drugs could be adjusted. Outcomes of interest included baseline characteristics; the percentage of persons with 25%, 50%, and 75% reductions in seizure frequency and with zero seizures; investigator-rated clinical status; and mean scores on the Habilitative Improvement Scale and the Aberrant Behavior Checklist. The small sample size did not allow for sufficient power for statistical comparisons between groups.Results: Demographics and baseline clinical characteristics were similar between groups (31 institutional and 36 community residents) except institutional residents were more likely to have severe or profound mental retardation and complex partial and partial secondarily generalized seizures. The percentages of persons with 25%, 50%, and 75% reductions in seizure frequency and zero seizures were 64%, 50%, 29%, and 18% respectively, for community residents and 42%, 38%, 23%, and 12% for institutional residents. Investigator-rated clinical status at the end of the Maintenance Phase was improved versus baseline in 68% of community residents and 62% of institutional residents. Most individuals (81% of institutionalized persons, 69% of community-dwelling persons) were considered to have experienced no change in adverse events with the addition of lamotrigine. The mean Habilitative Improvement Scale score was significantly improved ( p ≤ 0.05) versus baseline at the end of the Escalation, Maintenance, and Optimization Phases in both groups.Conclusio27 n: The efficacy and tolerability of lamotrigine were similar between institutional residents and community residents despite the numerically higher prevalence of severe or profound mental retardation among institutional residents.