Results:
In the primary study, 59 970 persons met selection (or inclusion) criteria; 36.7% of persons with newly diagnosed epilepsy remained untreated up to 3 years after diagnosis. In the validation study (N = 30 890), 31.8% of persons remained untreated up to 3 years after diagnosis. Lack of AED treatment was associated with an adjusted incidence rate ratio (95% confidence interval) of 1.2 (1.2-1.3) for medical events, 2.3 (2.2-2.3) for hospitalizations, and 2.8 (2.7-2.9) for emergency department visits.