Sample selection and the natural history of disease. Studies of febrile seizures
J. H. Ellenberg and K. B. Nelson
We have compared published reports on the frequency of unfavorable sequelae
in a common disorder of childhood, febrile seizures, as ascertained from
hospital clinics or referral units, with the frequency as reported from
population-based studies. Studies on defined populations, in which the
attempt was made to recognize and follow up all affected persons regardless
of medical care sought for the condition, are in close agreement and
indicate relatively low rates of unfavorable sequelae. Clinic-based studies
of febrile seizures have reported disparate results, including high
frequencies of adverse outcomes. A possible explanation is that patients in
clinic-based studies may not be representative of persons with the disorder
in the general population.
