ABSTRACT
OBJECTIVE: To validate six indirect methods which evaluate observance of therapy for arterial hypertension (AHT). DESIGN: Prospective study. SETTING: Urban health centre, Huelva. PATIENTS: 90 individuals (25 men and 65 women) (average age 59.2 +/- 11) chosen at random from the AHT clinic. MEASUREMENTS AND MAIN RESULTS: Home-based survey and review of clinical records. We counted hypotensive tablets at the start of the study and after a month. The indirect methods studied were: Self-communicated compliance (SC), attendance for appointments (AA), control of arterial pressure (CP), Morinsky-Green test (MG), knowledge of the illness (KI) and medical opinion (MO). We used the counting of tablets as the standard method. We studied the prevalence of non-observance, validity (2 x 2 table) and the concordance of the different methods. Prevalence of non-compliance was 16.7% (p = NS for age and gender). The average Systolic AP and Diastolic AP of compliers and non-compliers were 137 and 147 mmHg (p < 0.035) and 83 and 90 mmHg (p < 0.006), respectively. CONCLUSIONS: We found a high level of compliance. The SC underestimated non-compliance, which was overestimated by the other methods. We recommend SC and MO for detecting the non-complier, as they have greater specificity and better positive predictive values; and KI for detecting the complier, as it has greater sensitivity and negative predictive value. However these conclusions should be treated cautiously, since concordance of the different tests regarding the counting of tablets is weak.
