Epidemiologic survey of epilepsy among Army draftees in Lombardy, Italy

The prevalence and demographic distribution of treated epilepsy: a community-based study in Tasmania, Australia

OBJECTIVES

To estimate the prevalence and demographic distribution of treated epilepsy in a community-based population.

MATERIALS & METHODS

We surveyed all residents in Tasmania, Australia, who were supplied at least one antiepileptic drug prescription between July 1, 2001 and June 30, 2002, recorded on the national prescription database. We adjusted for the effect of disease-related non-response bias by imputation methods.

RESULTS

After three mail contacts, 54.0% (4072/7541) responded, with 1774 (43.6%) indicating treatment for epilepsy, representing 86.0% of the estimated total possible cases in Tasmania. The adjusted treated epilepsy prevalence was 4.36 per 1000 (95% CI 4.34, 4.39); lower in women (prevalence ratio 0.92 (95% CI 0.84, 1.00)); greater with increasing age (P < 0.001); similar in the three main geographic regions; and similar with socioeconomic status of postcode of residence.

CONCLUSIONS

Although our estimates are likely to be affected by access to health services, overall treated epilepsy prevalence of 4.4 per 1000 is similar to previous studies. Our finding of high elderly prevalence has been reported in a few recent studies in developed countries and has important clinical and public health implications in populations with similar aging demographics.

Epidemiology of idiopathic generalized epilepsies

Idiopathic generalized epilepsies (IGEs) are a relatively new category of disorders defined by strict clinical and electroencephalogram (EEG) features proposed by the International League Against Epilepsy (ILAE) classification of epileptic syndromes. IGEs are usually easy to diagnose when clinical and EEG data are collected, but epilepsy is not synonymous with epileptic syndrome. So far, IGEs are studied in the large group of epilepsies of undetermined or unknown etiology although the genetic origin is now largely accepted. ILAE-proposed criteria are helpful in the clinical and therapeutic management of IGEs, but many epidemiologic studies still confuse the cryptogenic and idiopathic groups. Some syndromes in childhood, which are completely described by strict electroclinical criteria such as the absence epilepsies, juvenile myoclonic epilepsies, are usually included and analyzed in epidemiologic studies; however, other epileptic syndromes observed in infancy, such as benign familial neonatal seizures and benign myoclonic epilepsy in infancy, are quite rare and are usually excluded from epidemiologic surveys because they are difficult to describe completely in electro-clinical terms. Another strong limitation in the study of epidemiology of IGEs is the lack of EEG data, either because EEG is not available or the routine EEG is normal. This is particularly relevant in the inclusion of patients with only tonic-clonic seizures. IGEs encompass several different syndromes, and a few patients shift from one phenotype to another. The overlapping of some syndromes during infancy and adolescence increased the difficulty to individualize strictly the correct syndrome. Many discrepancies can be observed in the distribution of the different syndromes included in the group of IGEs, because the strict criteria for classifying these syndromes proposed by the ILAE are often not respected. With this understanding, the general frequency of IGEs can be assessed at 15-20% of all epilepsies. The frequency and the distribution of incidence and prevalence of the different syndromes are tentatively reported and discussed. When the term idiopathic is used following the restrictive ILAE criteria, the mortality data concerning patients with idiopathic epilepsies do not show an increased standardized mortality ratio.

Prevalence of epilepsy. A door-to-door survey in the Sicilian community of Riposto

In a door-to-door survey of common neurological disorders in Sicily (SNES Project), we administered a screening symptoms questionnaire and a brief neurological examination to detect epileptic patients. All of the subjects effectively resident in the community of Riposto on 1 November 1987 (prevalence day) were investigated (n = 9956). The subjects with a positive questionnaire or a previous diagnosis of epilepsy were extensively examined by a neurologist and then definitively classified for epilepsy by a panel of senior neurologists. The crude prevalence of active and non-active epilepsy was 3.21/1000; the prevalence of active epilepsy alone was 2.71/1000. Of the 27 active cases, sixteen were affected by generalized tonic-clonic seizures, four by absences and four by complex partial attacks. All except two were being treated with antiepileptic drugs, most with phenobarbital. Our prevalence rate is lower than that reported by most authors, but similar to the rates in other Sicilian communities.

Epilepsy in an Italian community as assessed by a survey for prescriptions of antiepileptic drugs: epidemiology and patterns of care

The prescriptions of antiepileptic drugs in the years 1985 and 1986 were used to identify all possible cases of epilepsy in a population of about 50,000 people. The general practitioners of the study area filled out a questionnaire for each user of antiepileptic drugs registered as a patient of theirs. This information was integrated using data obtained by local specialist services or directly collected by visits and/or phone interviews. Two-hundred and fifty-six of the 417 antiepileptic drug users proved to be active epileptics with a prevalence rate of 5.2/1000, the annual incidence rate for 1986 being 51.8/100,000. The main patterns of the disease appeared to be consistent with those of the literature while the prior history of seizures in the previous five years was generally lower. The health care of epileptic patients involved a wide range of specialists. The general practitioners were responsible for the final diagnosis of epilepsy in 10% of patients and for the management of the disease in 22%, most of the patients being over 50 years old. The calculated mean prescribed daily doses of the antiepileptic drugs suggested that many epileptics were taking therapeutic schedules lower than those of the literature.