A validation of the new definition of drug-resistant epilepsy by the International League Against Epilepsy.
OBJECTIVE
To establish applicability, the recently proposed International League Against Epilepsy (ILAE) consensus on drug-resistant epilepsy (DRE) requires testing in clinical and research settings. This study evaluates the reliability and validity of these criteria in a clinical population.


METHODS
In phase I, two independent evaluators reviewed 97 randomly selected medical records of patients with epilepsy at two separate intervals. Both ILEA consensus and standard diagnostic criteria were employed. Kappa, weighted kappa, and intraclass correlation coefficient (ICC) were used to determine interobserver and intraobserver variability. In phase II, ILAE consensus criteria were applied to 250 patients with epilepsy to determine risk factors associated with development of DRE and to calculate point prevalence.


RESULTS
The interobserver agreement of the four definitions was as follows: Berg (0.56), Kwan and Brodie (0.58), Camfield and Camfield (0.69), and ILAE (0.77). The intraobserver agreement of the four definition was as follows: Berg (0.81), Kwan and Brodie (0.82), Camfield and Camfield (0.72), and ILAE (0.82). The prevalence of DRE was the following: with the Berg's definition was 28.4%, Kwan and Brodie 34%, Camfield and Camfield 37%, and with ILAE was 33%.


CONCLUSIONS
This is first study to establish reliability and validity of ILAE criteria for the diagnosis of DRE. This new definition compares favorably with previously established constructs, which continue to retain clinical significance.
Division of Neurology, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Jose F
JF
Téllez-Zenteno
Lizbeth
L
Hernández-Ronquillo
Samantha
S
Buckley
Ricardo
R
Zahagun
Syed
S
Rizvi
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants / Q000627:therapeutic use*; D032921:Consensus; D004351:Drug Resistance; D004827:Epilepsy / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015995:Prevalence; D015203:Reproducibility of Results; D055815:Young Adult
D000927:Anticonvulsants
Consensus; Drug-resistant epilepsy; Reliability; Validation; Validity