The unknown cost of epilepsy misdiagnosis in England and Wales

The article by Juarez-Garcia et al. on the costs of epilepsy misdiagnosis in England and Wales makes interesting reading. The need for comprehensive epilepsy services to minimise misdiagnosis of epilepsy, and reduce its associated costs is not in doubt. The terminology used by the authors and some the assumptions made, however, need clarification. The estimated prevalence of epilepsy in England and Wales (7.7/1000) and a misdiagnosis rate of 23% were used to estimate that 92,000 people were ‘‘misdiagnosed’’ with epilepsy in 2002. It is not clear why prevalence figures were used, given that most misdiagnosis estimations are based on consecutive referrals (first attendance rate as surrogate for incidence) to specialist clinics-highly selected cohorts in any case, not representative of the wider population of people suspected to have epilepsy. Furthermore, assumptions about costs at time of diagnosis or misdiagnosis (incident cases) and later in disease course (prevalent cases) differ considerably and using one or the other inappropriately introduces considerable error to any overall cost estimate. The number of people misdiagnosed with epilepsy each year is likely to be significantly less than the annual incidence of epilepsy (approximately 20,000/year in England andWales). The prevalence of inappropriate diagnosis among the general population is not known, but may be estimated from community-based prevalence studies. One such study in Wrexham, UK, circa 1995—1996 suggested