Abstracts

Rationale: Studies have identified that a significant proportion of patients with newly diagnosed epilepsy are not immediately started on anti-epileptic drug (AED) therapy, including in well-resourced countries, which could be regarded as a “treatment gap.” The short and long-term seizure outcomes of deferred treatment in a real-world cohort of patients with newly diagnosed epilepsy were studied. Methods: We recruited patients who attended the First Seizure Clinics of publicly funded hospitals in Western Australia between 1 May, 1999, and 31 May, 2016. The clinics assess and follow-up patients with new-onset seizures. Patients who fulfilled the ILAE 2014 diagnostic criteria for epilepsy were included. We reviewed the medical records to assess anti-epileptic drug therapy initiation and seizure occurrence throughout follow-up. Results: 598 patients were identified with newly diagnosed epilepsy, 369 (61.7%) male, median age at diagnosis 39 years (interquartile range [IQR]: 24-56). 347 were immediately initiated on therapy, and 251 were not. On multivariable analysis, patients not immediately treated had a higher rate of seizure recurrence during their untreated period than patients who had been immediately treated at diagnosis (hazard ratio [HR]=1.65, 95% confidence interval [CI] 1.35-2.02, p<0.0001) (Figure 1a). Those with epileptogenic neuroimaging also had a higher rate of recurrence (HR=1.42, 95% CI 1.15-1.74, p=0.001). Age, family history, prior febrile seizures, and epilepsy type had no relation to early seizure recurrence Patients with a single seizure but meeting 2014 ILAE diagnostic criteria for epilepsy had a lower rate of recurrence (HR=0.79, 95% CI 0.62-0.98, p=0.033) compared to those diagnosed after multiple seizures. 380 patients were followed up for more than one year after treatment initiation; 277 treated immediately on diagnosis, and 103 treated later during follow-up (median 4.3 years), usually after further seizures. 287 (75.5% of all) patients achieved at least one year of seizure freedom (Figure 2), 174 immediately, and the remainder took a median 119 weeks (IQR: 83-175). Immediate or delayed treatment had no significant impact on rate of seizure freedom achievement after treatment (Figure 1b), including in those with a single seizure at diagnosis. On multivariable analysis, the only factor that influenced rate of seizure freedom achievement was ethnicity, with a small (n=16) cohort of Indigenous Australians having poorer rates of achieving seizure freedom (HR=0.78, 95% CI 0.55-1.11). Whether the patient was diagnosed by new ILAE or traditional definition of epilepsy also had no impact, nor did the initial choice of new or old AED. Conclusions: Patients not immediately treated at diagnosis of epilepsy have a higher rate of seizure recurrence than those with immediate treatment. However, after treatment is initiated, patients with delayed treatment have similar long-term seizure outcomes to those immediately treated. In patients with a single seizure but meeting the new ILAE definition of epilepsy, immediate or delayed treatment had no impact on short- or long-term seizure outcomes. These real-world findings replicate those of randomized studies of first-ever seizure and indicate that neither early diagnosis via new ILAE criteria nor deferred treatment of newly diagnosed epilepsy affect long-term outcome. Funding: No funding