Refractory juvenile myoclonic epilepsy: a meta-analysis of prevalence and risk factors

Background and purpose: Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome for which treatment response is generally assumed to be good. We aimed to determine the prevalence and prognostic risk factors for refractoriness of JME. Methods: We systematically searched PubMed and EMBASE and included 43 eligible studies, reporting seizure outcome after antiepileptic drug (AED) treatment in JME cohorts. We defined refractory JME as persistence of any seizure despite AED treatment and performed a random-effects meta-analysis to assess the prevalence of refractory JME and of seizure recurrence after AED withdrawal in individuals with well-controlled seizures. Studies reporting potential prognostic risk factors in relation to seizure outcome were included for subsequent meta-analysis of risk factors for refractoriness. Results: Overall, 35% (95% confidence interval, 29–41%) of individuals (n = 3311) were refractory. There was marked heterogeneity between studies. Seizures recurred in 78% (95% confidence interval, 52–94%) of individuals who attempted to withdraw from treatment after a period of seizure freedom (n = 246). Seizure outcome by publication year suggested that prognosis did not improve over time. Meta-analysis suggested six variables as prognostic factors for refractoriness, i.e. having three seizure types, absence seizures, psychiatric comorbidities, earlier age at seizure onset, history of childhood absence epilepsy and praxis-induced seizures. Conclusion: One-third of people with JME were refractory, which is a higher prevalence than expected. Risk factors were identified and can be used to guide treatment and counselling of people with JME.