Abstracts

Rationale: For a long time there has not been an agreement to categorize patients as non-responder to drug treatment. Consequently, alternative therapies such as surgery could not be offered earlier. Recently, the ILAE has developed a new consensus definition of drug-resistance epilepsy. The aim of the study was to compare the new definition of ILAE with other five used in literature, and to investigate their practical application and operability.Methods: Five hundred and forty nine medical records of patients attending our Epilepsy Center between 2002 and 2003 were selected, with at least 5 years of follow-up. They were characterized according to each of the definitions: ILAE, HRM (our Center), Connecticut, Philadelphia, Canada and Scotland in resistant or not resistant. Concordance between the definitions was determined by kappa coefficient, and the most discordant were compared by test of proportions.Results: One hundred and ninety three patients could be analyzed and categorized according to the classifications used. 118 patients were men (61%). Average age of diagnosis: 15.3 12.05 years (range <1-69); current average age: 37 12.5 years (range 15-78). Time of evolution of epilepsy: 21.8 12.0 years (range 3-66); follow-up time: 7.5 0.5 years (range 7-8). Average number of drugs used per patient: 2.3 1.2 (range 1-7). The highest concordance was found between the definitions of the ILAE and Scotland (0.979) and the lowest concordance between the ILAE and the one used in our Center (0.587). The one which included more refractory patients was the ILAE, and the lowest was our own classification (p <0.0001).Conclusions: The new definition of drug-resistant epilepsy, proposed by the ILAE, was applicable and gave results similar to most of the classifications previously used. Other variables, besides the number of drugs used and the seizure-free time, should be taken into account in order to establish accurately the resistance to treatment.