A Prospective Study on Long-term Outcome and Potential Usefulness fo an Intervention Aimed at Reducing Adverse Effects in Patients With Refractory Epilepsy

With a prevalence of about 0.8% in the general population, chronic active epilepsy is the most common serious neurological disorder and affects 3.7 million people in the EU alone. While the majority of patients with epilepsy can be fully controlled by available medications, about 40% fail to achieve seizure control. Refractory epilepsy is associated with poor quality of life (QoL), due to the consequences of seizures, the burden of adverse effects of antiepileptic drugs (AEDs), and associated comorbidities, especially depressed mood. In addition to human suffering, refractory epilepsy entails major costs: observational studies in Italy estimated an annual medical costs at 2,190 in adults, or 3,268 euros in children.

The study had a prospective design and mainly observational design (core study). A subgroup of patients, participated in a randomized assessment (controlled study) of the impact of utilizing a standardized tool for the assessment of adverse effects.

For the core study, the study population was represented by 1,000 consecutive consenting patients with refractory epilepsy seen as in- or outpatients at 10 major secondary/tertiary referral centres in Italy. "Refractory epilepsy" was defined as "the persistence of seizures after adequate attempts with the maximally tolerated dosage of one or more appropriate primary AEDs, excluding situations where a meaningful dose escalation was prevented by allergic or idiosyncratic adverse reactions" and at least one seizure during the previous 3 months while at steady state on the current treatment schedule. The degree of refractoriness was classified into categories.

A subcohort of patients included in the study took part in a randomized assessment of the usefulness of providing the treating physician with a standardized assessment of the adverse effect profile. The subcohort was represented by all patients enrolled in the core study who met at the first assessment visit the following additional eligibility criteria: (i) age >16 years; (ii) no progressive disorder; (iii) ability to complete the Adverse Profile AEP questionnaire, and (iv) an AEP score >=45.

For the core study, the approach was observational and the study did not interfere with clinical management. All patients were treated as considered best by the attending physician. Results of questionnaires were not made available to the treating physician until the end of the study, except for the AEP questionnaire data that were fed back to the physician only for a subgroup of patients included in the randomized assessment.