Tradução, adaptação transcultural e validação da versão em português do Brasil da General Medication Adherence Scale (GMAS) em pacientes com hipertensão arterial sistêmica

Abstract

Non-adherence to antihypertensive treatment has a negative impact on blood pressure control. There are several strategies to measure adherence to antihypertensive drug treatment, classified as direct and indirect methods. Direct methods are performed through biological analysis (blood or urine). However, they are high-cost alternatives and only available in research environments. In the indirect methods, self-report scales stand out, which are a safe and cost-effective option, as they are simple, low-cost, applicable in various environments and provide immediate feedback, therefore being easy to incorporate into the daily clinical practice. However, to be widely used, an adherence rating scale must be tested and validated, in addition to being available for use at no additional cost. Given the above, the objective of the present study was to validate the General Medication Adherence Scale (GMAS) into Brazilian Portuguese in patients with Systemic Arterial Hypertension. Therefore, this research was carried out in two phases. At first, the cross-cultural validation process of the GMAS instrument from English to Brazilian Portuguese was carried out. This process involved the stages of translation, cross-cultural adaptation and validation and used the methodology described by Beaton et al. In the second phase, a cross-sectional study was carried out in the cardiology sector of hospitals, public and private, in Maceió (AL, Brazil), through the application of the instrument through structured interviews to patients diagnosed with hypertension. In this step, the following analyzes were performed: internal consistency through reliability and test-retest; intraclass correlation coefficients; and Pearson's correlation coefficient to assess content validity. The assessment of convergent validity was performed using the Brief Medication Questionnaire (BMQ) scale. In addition, measurements of blood pressure, measurements of anthropometric parameters and 24-hour ABPM Examination were carried out. Translation and cross-cultural validation generated a Portuguese version of the GMAS scale that was applied to 123 patients. As for the sample, most patients were female (67.5%), and the mean age was 58.47 ± 11.8 years. The scale's internal consistency was 0.75, and its reproducibility could be measured by test-retest, performed using Spearman's correlation (0.761; p<0.001). As for convergent validity, when comparing GMAS and BMQ, they obtained a degree of 77.6% for adherent behavior (p < 0.05). Finally, the discriminant validity was evaluated according to criteria established by the author of the original version of the scale and a relationship between age and adherence was identified, with non-adherent behavior being more frequent among patients considered younger (<45 years) (p <0. 05). The constructs evaluated for adherence were behavior (n=90.73.2%), treatment (n=103, 83.7%) and cost (n=81.65.9%). In view of this, the Brazilian Portuguese version of the GMAS is a valid and reliable tool to measure adherence in patients with hypertension.