Seizure relapse and development of drug resistance following long-term seizure remission.
OBJECTIVE
To quantify and identify predictive risk factors for seizure relapse and development of drug resistance in patients who achieved long-term (>1 year) antiepileptic drug-induced seizure remission.


METHODS
Prospective cohort study.


METHODS
Epilepsy Center, Rambam Medical Center. Patients Two hundred fifty-six consecutive patients who entered long-term (>1 year) antiepileptic drug-induced seizure remission were followed up prospectively for 2 years or more.


METHODS
Seizure relapse and development of drug-resistant epilepsy.


RESULTS
Five years after entering seizure remission, 40.2% of patients experienced seizure relapse and 25.3% of patients developed drug-resistant epilepsy. The Kaplan-Meier curves could be fitted by monoexponential functions, with a maximal seizure relapse rate of 43.6%, maximal drug-resistance rate of 27.4%, and half-decay constant of 21.5 months for both curves. Treatment history served as a significant independent prognostic risk factor for both seizure relapse and development of drug resistance. The preremission seizure frequency and duration of epilepsy were also identified as significant prognostic risk factors in the univariant analysis but failed to reach statistical significance in the multivariate analysis.


CONCLUSIONS
Seizure relapse commonly occurs in patients following long-term seizure remission. Treatment history and duration of epilepsy are predictive risk factors for both seizure relapse and development of drug resistance.
Schiller
Yitzhak
Y
Epilepsy Service, Department of Neurology, Rambam Medical Center, 1 Efron St, Haifa 31096, Israel. y_schiller@yahoo.com
D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use*; D015331:Cohort Studies; D004351:Drug Resistance; D004569:Electroencephalography; D004827:Epilepsy / Q000188:drug therapy* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008134:Long-Term Care; D008297:Male; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012640:Seizures / Q000188:drug therapy* / Q000453:epidemiology / Q000209:etiology; D016019:Survival Analysis
D000927:Anticonvulsants