Measurement of compliance through patient interviews.

In this study different indices for compliance with antiepileptic drug (AED) treatment were derived from a sample of 41 patients with epilepsy, coming for the first time to an out-patient clinic: forgetting a dose, aids for drug intake (e.g., a pill box), tying intake to stable habits, intake at weekends, taking less than prescribed, taking more than prescribed, expected physical harm as a consequence of drug intake. Significant interrelations were found between reporting having thought of discontinuation because of physical harm and actual discontinuation in the past (P = 0.04), between use of an aid and tying intake to stable habits in the morning, at noon and in the evening (P = 0.01, P = 0.03, P = 0.08). There was a relation between using an aid and plasma levels of AEDs (P = 0.03). Finally an index was constructed from the different measures for intake behaviour. There was a correlation r = -0.60 with coefficients of variation for phenytoin, carbamazepine and phenobarbital (P = 0.05).