IJCS | Volume 33, Nº3, May / June 2020

275 Table 3 - Reasons for lack of adherence and percentage of positive responses in the Morisky-Green-Levine test Questions Positive answers (%) 1. Do you ever forget to take medications for your hypertension? 15.8 2. Are you careless with the time you should take the medication? 25.6 3. When you are well, do you stop taking the medication? 4.5 4. If you ever feel bad, do you stop taking it? 2.0 1-2. Execution. 3-4. Short persistence. Table 4 - Characteristics of patients by adherence or not to pharmacological treatment Adherence n = 530 Non- adherence n = 322 p-value Age (years) 63 ± 13 57 ± 15 < 0.001 SBP (mmHg) 136 ± 17 142 ± 19 < 0.001 DBP (mmHg) 80 ± 11 85 ± 12 < 0.001 BMI (Kg/m 2 ) 29.0 ± 5.5 29.7 ± 6.8 0.094 Hypercholesterolemia (%) 41.1 36.6 0.194 Diabetes mellitus(%) 23.4 28.5 0.092 Never-smoking (%) 83.0 76.7 0.024 Previous cardiovascular event* (%) 5.6 9.6 0.029 Number of antihypertensive drugs 1.7 ± 0.8 1.5 ± 0.8 0.056 Fixed-dose drug combination (%) 17.4 4,7 < 0.001 SBP: systolic blood pressure; DBP: diastolic blood pressure; BMI: body mass index Espeche et al. Adherence to antihypertensive therapy in Argentina Int J Cardiovasc Sci. 2020; 33(3):272-277 Original Article patients (BMI > 35 kg/m 2 ) were less adherent than the rest of the sample. The use of fixed-dose combination antihypertensives was more frequent in adherent than non-adherent patients (p < 0.001). In the logistic regression analysis, previous cardiovascular event was independently associated with lack of adherence (OR = 3.01 95%CI 1.53-5.91). Conversely, fixed-dose drug combinations (OR = 0.22 95%CI 0.12-0.40) and older age (OR = 0.97 95%CI 0.96-0.0.98)were factors associatedwithhigher adherence. Discussion In our study the prevalence of individuals adherent to antihypertensive medication (62.2%) was greater than that previously published using the same test (the Morisky scale). 17 In most previously published studies, adherence to pharmacological treatment was evaluated using different direct and indirect tests, and consequently, comparisons between studies are difficult. It is of note that the prevalence of hypertensive patients with controlled hypertension in this study, 45.4%, was higher than those reported in other studies performed in Argentina (7-43%). 15 However, since all patients included were treated with antihypertensive drugs, the comparison of the level of control of hypertension between different sample populations is not adequate. As expected, individuals with controlled BP show a higher adherence rate (69.3% vs 53.3% p < 0.001). Interestingly, the use of fixed-dose combination was associated with both higher rates of adherence and higher rates of BP control. Although, in theory, the use of more antihypertensive drugs could be related to lower adherence, in this study the number of drugs did not differ significantly between adherent vs. non-adherent group. Since multiple drug treatments are often required in hypertension control, 16 fixed-dose drug combination may be an adequate approach to the “more drugs vs . better adherence” dilemma. Analyzing the variables related to adherence, never- smoking was protective factor. We can hypothesize that avoiding the initiation of tobacco use has not only a beneficial effect on the prevention of chronic diseases, but also an indirect effect on improving adherence. Indeed, the non-adherent group had more frequent previous history of cardiovascular events. This could represent reverse causality and highlight that improving adherence in adult patients is a very difficult task. Regarding the reasons of non-adherence to antihypertensive drug treatment, Burnier et al. 6 identified two different mechanisms: 1-short persistence, i.e., when the patients ceased their engagement with the dosing