Validity of six indirect methods to assess drug therapy compliance for Hypertension

Abstract

Objective. To validate six indirect methods, which were simple and easy to apply in clinical practice, of identifying patients who did not comply with drugs treatment for Hypertension.

Design. A prospective study based on two visits to patient´s home.

Setting. Rural Health Centre at Calpe, Alicante.

Patients. 174 patients (58 men and 116 women) were included. They were chosen at random from the Centre´s records of hypertense patients.

Measurements and main results. Compliance was assessed by the method of a surprise counting of pills in the patient´s home. Patients who had between 80 and 110% compliance were defined as compliant. The six indirect methods validated were: Communication of self-compliance (CS), Attendance at appointments (AA), Doctor´s judgment (DJ), Information about the illness (II), Hypertension control (HC) and the Morisky-Green test (MG). II was the most sensitive (81.9%). CS reached the highest specificity (93.4%), the best positive predictive value (81.8%) and the best concordance index (Kappa, 0.26).

Conclusions. II and CS are the indirect methods with the best validity indicators and could be used together to assess compliance with drugs treatment for Hypertension.