Association between the 8-item Morisky Medication Adherence

Scale (MMAS-8) and Blood Pressure Control

Alfredo Dias Oliveira-Filho, Jos Augusto Barreto-Filho, Sabrina Joany Felizardo Neves, Divaldo Pereira de Lyra Junior
Laboratrio de Ensino e Pesquisa em Farmcia Social (LEPFS), Curso de Farmcia, Universidade Federal de Sergipe, Departamento de Farmcia
e Nutrio, Universidade Federal de Alagoas, Departamento de Medicina, Universidade Federal de Sergipe, SE - Brazil

Abstract
Background: Non-adherence to treatment is an important and often unrecognized risk factor that contributes to reduced
control of blood pressure (BP).
Objective: To determine the association between treatment adherence measured by a validated version in Portuguese of
the 8-item Morisky Medication Adherence Scale (MMAS-8) and BP control in hypertensive outpatients.
Methods: A cross-sectional study was carried out with hypertensive patients older than 18 years, treated at six of the
Family Health Strategy Units in Macei (AL), through interviews and home blood pressure measurements, between
January and April 2011. Adherence was determined by MMAS-8 version translated for this study. The patients were
considered adherent when they had a score equal to 8 at the MMAS-8.
Results: The prevalence of adherence among the 223 patients studied was 19.7%, while 34% had controlled BP (>
140/90 mmHg). The average adherence value according to the MMAS-8 was 5.8 ( 1.8). Adherent patients showed to
be more prone (OR = 6.1, CI [95%] = 3.0 to 12.0) to have blood pressure control than those who reached mean (6 to
<8) or low values (<6) at the adherence score. The Portuguese version of MMAS-8 was showed a significant association
with BP control (p = 0.000).
Conclusion: The diagnosis of non-adherent behavior through the application of MMAS-8 in patients using of antihyperten-
sive medications was predictive of elevated systolic and diastolic BP. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0)
Keywords: Medication adherence; blood pressure; outpatients; health systems.

Introduction clinics, provided by the Brazilian Public Health System (SUS),

particularly through the Family Health Strategy, is still ignored4.
In patients with systemic arterial hypertension (SAH), non-
Thus, the systematic diagnosis of non-adherence is crucial to
adherence is an important and often unrecognized risk factor
investigate its impact on clinical outcomes.
that contributes to the reduced control of blood pressure (BP),
leading to the development of other cardiovascular diseases In this context, the most widely used method of adherence
such as heart failure, coronary artery disease, renal failure and assessment is the Morisky Medication Adherence Scale (MMAS
cerebrovascular accident1. 4- item version)5. Recently, a new eight-item scale (MMAS-8),
which has greater reliability (a = 0.83 vs. = 0.61)6, created with
Studies comprehending five decades have estimated that
the objective of determining adherence to antihypertensive
20% to 50% of patients do not take their medications as
treatment, was developed from the MMAS-4 and supplemented
prescribed2. According to the World Health Organization
with additional items designed to address several aspects of
(WHO), in developed countries, non-adherence of patients
adherence behavior. In Brazil, studies evaluating non-adherence
with chronic diseases is around 50%, being probably higher
with the new scale are still recent and scarce7.
in developing countries3.
The present study aimed to determine the relationship
Although the prevalence and implications of non-adherence
between adherence measured from a validated version in
on clinical outcomes have been increasingly acknowledged, Portuguese of the MMAS-8 and BP control in hypertensive
the true impact of measures known to be effective in BP outpatients treated by the Family Health Strategy teams.
control, such as cost-free pharmacotherapy given at outpatient
Methods
Mailing Address: Divaldo Pereira De Lyra Junior
Cidade Universitria Prof. Jos Alosio de Campos - Av. Marechal Rondon, Study design, setting and period
s/n Jardim Rosa Elza. CEP 49100-000, So Cristovo, SE - Brazil.
E-mail: lepfs.ufs@gmail.com, lyra_jr@hotmail.com A cross-sectional study was carried out by applying a
Manuscript received July 28, 2011; revised August 11, 2011; accepted Janu- structured interview to hypertensive patients treated by the
ary 17, 2012. Family Health Strategy teams.
 Oliveira-Filho et al
Medication adherence vs. blood pressure control

The interviews occurred in six Family Health Units (USF) The MMAS-8, an update with greater sensitivity of the
of Maceio linked to the second edition of Health Tutorial four-item scale published in 1986 and considered the most
Education Program (PET-Saude II) between January and commonly used self-reporting method to determine adherence,
April 2011. contains eight questions with closed dichotomous (yes / no)
answers, designed to prevent the bias of positive responses
Study Population from patients questions asked by health professionals, by
reversing the responses related to the interviewees adherence
We selected patients with confirmed diagnosis of
behavior6,16. Thus, each item measured a specific adherence
hypertension who were treated at the USF, aged 18
behavior, with seven questions that must be answered
or older and who used antihypertensive medications.
negatively and only one positively, with the last question being
Patients with secondary hypertension confirmed by
answered according to a scale of five options: never, almost
medical records or who had purchased at least one never, sometimes, often, and always.
antihypertensive drug in the thirty days preceding the
interview were excluded. This exclusion criterion was The degree of adherence was determined according to the
aimed to eliminate the interference of the cost of drugs, score resulting from the sum of all the correct answers: high
one of the major predictive factors of nonadherence8. adherence (eight points), average adherence (6 to < 8 points)
and poor adherence (< 6 points)17. In this study, patients were
considered adherent when they had a score equal to eight
Interviews and assessed variables in the MMAS-8.
The interviews were carried out in the patients houses, by To assess the internal consistency, we used the item-total
previously trained students of pharmaceutical sciences who correlation and Cronbachs alpha.
were members of the PET-Health and who were monitored
during the home visit by a health agent of the USF. The
Sample size
following variables were investigated: gender, age, schooling,
regular physical activity, alcohol consumption, smoking, drugs, Considering the original study by Morisky et al., where
amount of medication, time of use of antihypertensive drugs, 16% of patients achieved a score of 8 at the MMAS-8, as
systolic blood pressure (SBP), diastolic blood pressure (DBP) well as absolute accuracy of 5% and confidence interval of
and blood pressure control, characterized by BP values < 95%, a sample of 207 individuals was determined. In order
140/90 mmHg, respectively. to correct any losses and provide a better breakdown of the
independent variables, the sample size was adjusted by a
Patients with uncontrolled blood pressure were classified
proportional factor of 1.25. Thus, the sample size for this
as patients with resistant or pseudoresistant hypertension,
study was established at 230 patients. The number of patients
according to the literature9-11. The values of systolic (SBP)
needed to assess the internal consistency was considerably
and diastolic (DBP) blood pressure were obtained by the
lower, being obtained by Non-Parametric Approach to
mean of two blood pressure measurements, carried out by
Calculate Sample Size Based on Assessment Questionnaires
the research team during the visit, according to the guidelines
or Scales in Healthcare Area, developed by Couto Jr.18,
established in the VI Brazilian Guidelines for the Treatment
which estimates the sample size by the number of items and
of Hypertension9, using a mercury sphygmomanometers
categories of the data collection instrument.
calibrated with a minimum interval of 5 minutes between
each measurement. To reduce the influence of the white-coat
effect - defined as a persistently increased blood pressure at Statistical Analysis
the medical office, compared with measurements at home Data analysis was performed using SPSS software, release
or after 24-hour ambulatory blood pressure monitoring 12. Statistical analyzes involved: descriptive analyzes, the
(ABPM) - on BP values, the measurements were taken at Kolmogorov-Smirnov test to check the normality of continuous
the patients homes12,13. variables, chi-square and Kruskal-Wallis test to test the
Adherence was measured using the eight-item Morisky relationship between adherence and other independent
Medication Adherence Scale (MMAS-8)6, translated into variables, and binary logistic regression. All variables with p
< 0.25 in the bivariate analysis were included in the initial
Brazilian Portuguese (chart 1) and validated for the present
model of the multivariate analysis. Then the variables that
study. To obtain conceptual equivalence, the MMAS-8 was
showed a higher value of p were removed, one by one, until
translated in accordance with the recommendations for
only variables with statistical significance remained in at least
translation and cultural adaptation of Beaton et al.14, Wild
one of the categories of therapeutic adherence. The level
et al.15, which require the translation and back-translation
significance was set at < 5%.
by bilingual translators, some of which are independent.
After evaluation and approval by the author of the scale, the
translated version was tested in a group of 20 patients with Ethical Aspects
hypertension to check for understanding of the questions in The study was approved by the Ethics Committee in
accordance with its original meaning. The questions were Research of Universidade Federal de Alagoas on 11/06/2009,
understood identically by all, and subsequent alterations were protocol# 010186/2009-01. Data were collected only after
not considered necessary. the informed consent had been signed by all patients.

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 Oliveira-Filho et al
Medication adherence vs. blood pressure control

Chart 1 medications were hydrochlorothiazide (to 53.3% of patients),

captopril (49.9%), propranolol (14.3%), enalapril (12.1%),
New 8-item Morisky Medication Adherence Scale- MMAS-8
amlodipine (11.2%), atenolol (8.5%) and losartan (4.9%). Most
1) Do you sometimes forget to take your blood pressure medication? patients (52.5%) had been using the same anti-hypertensive
2) In the last two weeks, was there any day when you did not take your high drug therapy for five years or more, 20.2% had used the same
blood pressure medication? treatment for three or four years, 12.6% had used it for one
3) Have you ever stopped taking your medications or decreased the dose to two years; 8 5% from six months to a year, and 6.3%, for
without first warning your doctor because you felt worse when you took them? less than six months.
4) When you travel or leave the house, do you sometimes forget to take your Antihypertensive monotherapy was prescribed to 47.1%
medications? of patients; 45.3% were taking two antihypertensive drugs
5) Did you take your high blood pressure medication yesterday? and 7.1% were using three or more drugs, one of which was
6) When you feel your blood pressure is controlled, do you sometimes stop a diuretic. While 36.2% of patients on monotherapy and
taking your medications? 36.6% of patients taking two drugs had controlled blood
7) Have you ever felt distressed for strictly following your high blood pressure pressure (Table 2), only 5.9% of patients using three or more
treatment? antihypertensive drugs had the same outcome (p = 0.038).
8) How often do you have difficulty to remember taking all your blood pressure
Among patients with uncontrolled blood pressure, 2.7%
medications?
(1.8% of total patients) were both adherents and users of triple
Never/ Almost never / Sometimes/ Frequently/ Always
antihypertensive therapy containing a diuretic, characterizing
resistant hypertension. The other patients who had elevated BP
values were divided as follows: 8.2% did not adhere to triple
Results therapy with a diuretic, 8.8% were adherent, but used one
We selected 231 patients, eight of whom declined to or two antihypertensive drugs, and 80.3 % were nonadherent
participate in the study (refusal rate = 3.5%). The mean age of and used
one or two antihypertensive drugs (Table 4).
patients was 57.18 years ( 12.7), with a minimum age of 27
and maximum of 85 years, and the majority (70.9%) of them Scale reliability
were females. Only 46 (20.6%) patients practiced some regular The corrected item-total correlation resulted in a value
physical activity. Smoking and alcohol consumption were < 0.20 for item 3, which was low, although significantly
reported by 10.3% and 18.8% of patients, respectively. None different from zero. However, the Cronbachs alpha values
of the variables investigated was associated with adherence resulting from the exclusion of each item were lower, without
or blood pressure control (Tables 1 and 2). exception, than the resulting coefficient ( = 0.69), indicating
that the inclusion of item 3 did not affect the instrument
Therapeutic adherence and blood pressure control reliability (Table 5).
Only 34.1% of patients had blood pressure under control.
The rate of therapeutic adherence (MMAS-8 = 8, high Discussion
adherence) was 19.7%. The mean adherence value according
Cardiovascular Diseases (CVD), of which main risk factor
to the MMAS-8 was 5.8 ( 1.8). Among patients considered
is hypertension19,20, are a major cause of mortality both
non-adherent, 33.2% had mean adherence, and 47.1%, low
worldwide and in Brazil, where they accounted for 32%
adherence. According to logistic regression analysis, patients
of deaths in individuals over 30 years in 200521. Several
who reached maximum values in the MMAS-8 showed to
BP control measures have been tested22,23; however, not
be more likely (OR = 6.1, [95%] CI = 3.0 to 12.0) to have
even the strong evidence that several antihypertensive drug
blood pressure control than those who attained mean (6 to
treatments are effective in reducing cardiovascular morbidity
<8) or low (<6) values. The association of BP control (p =
and mortality rates mean appropriate blood pressure (BP)
0.000) and mean SBP and DBP (p = 0.002510 and p =
control, due to poor adherence to treatment9,24. Studies of the
0.000135, respectively) with the degree of adherence can
Brazilian population indicate a BP control of 20% to 60%20,25-
be seen in Table 3. 27
, within the same range of BP control observed in our study.
Additionally, these associations can be used to investigate a According to literature, poor adherence affects the clinical
suspected sub-optimal adherence to therapy in patients with outcome and quality of life, causing adverse outcomes such
uncontrolled BP: 75.6% of patients with uncontrolled BP did as increased morbimortality and healthcare costs28. In the
not adhere to antihypertensive treatment, while 33.3% of treatment of hypertension, its first consequence is the failure
patients with BP under control were nonadherent. in BP control; several studies have shown this association, also
found in our study, in which significantly lower systolic and
Medication use diastolic pressures were observed among patients with a high
The mean number of drugs prescribed per patient was 3.15 degree of adherence6,29,30.
( 1.63, 3.11 among adherent, and 3.16 among non-adherent The dichotomous categorization of adherence in adherent
patients) and the mean number of antihypertensive drugs per vs. nonadherent patients was based, as in the original study,
patient was 1.61 ( 0.65; 1.51 and 1.67 in adherents and on the association between the scale and blood pressure
non-adherents, respectively). The most frequently prescribed control. However, in this study, only those patients with high

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 Oliveira-Filho et al
Medication adherence vs. blood pressure control

Table 1 Therapy adherence, sociodemographic characteristics and life habits of hypertensive patients, Macei, AL, 2011

Adherent Non-adherent
Variable
n (%) n (%)

Age
18-29 0 0 2 100
30-39 4 17.4 19 82.6
40-49 8 27.6 21 72.4
50-59 11 18.6 48 81.4
60-69 20 28.2 51 71.8
70 or older 8 21.6 29 78.4

Gender
Female 37 23.4 121 76.6
Male 14 21.5 51 78.5

Number of drugs
1 7 25.9 20 74.1
2-3 23 20.7 88 79.3
4-5 17 28.8 42 71.2
6 4 20.0 22 80.0

Number of anti-hypertensive drugs

1 24 22.9 81 77.1
2 23 22.8 78 77.2
3 4 28.6 10 71.4
4 - - 3 100.0

Time of anti-hypertensive treatment

< 1 year
9 27.3 24 72.7
1 a 2 years
9 32.1 19 67.9
2 a 4 years
6 13.3 39 86.7
5 years
27 23.1 90 76.9

Level of Schooling
Illiterate 27 21.4 99 78.6
Elementary School 12 21.4 44 78.6
High School 12 32.4 25 67.6
College or University 0 0 3 100

Physical Activity
Yes 15 32.6 31 67.4
No 36 20.5 140 79.5

Smoker
Yes 5 21.7 18 78.3
No 46 23.0 154 77.0

Regular alcohol consumption

Yes 5 12.2 36 87.8
No 38 21.3 140 78.7

Controlled BP *
Yes 34 44.7 42 55.3
No 17 11.6 130 88.4

* p = 0.000; Pearsons Chi-square.

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 Oliveira-Filho et al
Medication adherence vs. blood pressure control

Table 2 Blood pressure control, sociodemographic characteristics and life habits of hypertensive patients, Macei, AL, 2011

Controlled BP Uncontrolled BP
Variable
n (%) n (%)

Age (yrs.)
18-29 0 0 4 100
30-39 6 26.1 17 73.9
40-49 6 20.7 23 79.3
50-59 26 44.1 33 55.9
60-69 25 35.2 46 64.8
70 13 35.1 24 64.9

Gender
Female 53 30.3 105 69.7
Male 23 28.6 42 71.4

Number of medications*
1 10 37.0 17 63.0
2-3 39 35.1 72 64.9
4-5 19 42.4 40 57.6
6 8 26.7 22 73.3

Number of anti-hypertensive drugs

1 38 36.2 67 63.8
2 37 36.6 64 63.4
3 1 7.1 13 92.9
4 - - 3 100.0

Time of anti-hypertensive treatment

<1 year
12 36.4 21 63.6
1 to 2 years
10 39.3 17 60.7
2 to 4 years
18 40.0 37 60.0
5 years
35 29.9 82 70.1

Level of schooling
Illiterate 40 31.7 86 68.3
Elementary School 21 58.3 35 41.7
High School 15 40.5 22 59.5
College or University 0 0 3 100

Physical activity
Yes 19 41.3 27 58.7
No 57 32.4 119 67.6

Smoker
Yes 7 30.4 16 69.6
No 69 34.5 131 65.5

Regular alcohol consumption

Yes 12 29.2 29 70.8
No 62 34.8 116 65.2

* p = 0.038; Pearsons Chi-square.

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 Oliveira-Filho et al
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Table 3 Association between the degrees of therapy adherence with BP control and mean BP values, Macei, AL, 2011

Blood Pressure Control * Mean Blood Pressure Values

Yes No SBP DBP

% % mmHg (DP) F (%)

Low adherence (<6) 19.4 80.6 135.7 (16.21) 95.3 (13.75)

Middle adherence (6 a <8) 37.0 63.0 133.0 (16.24) 92.2 (12.44)

High adherence (8) 65.1 34.9 125.5 (11.99) 85.3 (11.25)

BP control: systolic BP < 140 mmHg, diastolic BP < 90 mmHg

*(p = 0.000); Chi-square.
systolic BP (p = 0.002510); Kruskal-Wallis.
diastolic BP (p = 0.000135); Kruskal-Wallis.

Table 4 Corrected item-total correlation and tool reliability

Cronbachs Alpha if the

Item Corrected item-total correlation
item is excluded

1. Do you sometimes forget to take your blood pressure medication? 0,615 0,558

2. In the last two weeks, was there any day when you did not take your high blood
0,482 0,589
pressure medication?
3. Have you ever stopped taking your medications or decreased the dose without first
0,189 0,652
warning your doctor because you felt worse when you took them?
4. When you travel or leave the house, do you sometimes forget to take your
0,236 0,645
medications?

5. Did you take your high blood pressure medication yesterday? 0,353 0,626

6. When you feel your blood pressure is controlled, do you sometimes stop taking
0,405 0,614
your medications?

7. Have you ever felt distressed for strictly following your high blood pressure treatment? 0,234 0,645

8. How often do you have difficulty to remember taking all your blood
0,497 0,628
pressure medications?

= 0,689

Table 5 Anti-hypertensive drug therapy and treatment adherence of patients with uncontrolled BP (resistant and pseudoresistant
hypertension), Macei, AL, 2011

Adherent Adherent Total

Drug therapy
n (%) n (%)

Monotherapy or double therapy 13 8,8 118 80,3 131 89,1

Triple therapy with one diuretic agent 4* 2,7 12 8,2 16 10,9

*Resistant hypertension
Pseudoresistant hypertension

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 Oliveira-Filho et al
Medication adherence vs. blood pressure control

adherence (score of 8) were considered adherent, as this The most relevant component of the therapeutic regimen
group was associated with blood pressure control (Table 3). complexity is the number of prescribed drugs34. However,
In a study by Morisky et al.6 patients with high and medium no association was found between the number of drugs
adherence were considered adherent. used and their dosage, and treatment adherence.
Although the application protocols are identical, the As for the predictors of BP control, recently, the ALLHAT
results suggest that the interpretation of the score is study35 - a randomized clinical trial involving a large number
different, making the care target to be focused on improving of patients aimed to assess the control of hypertension
adherence behavior not only in patients with a low level of and the effects of antihypertensive drugs on clinical
adherence, but also those with a medium degree. In our outcomes - identified higher basal BP, Black ethnicity and
study, 65.1% of patients with high adherence and 37.0% of age as the main predictors of lack of BP control. Among
patients with medium degree of adherence had controlled the additional causes are the female gender, diagnosis of
BP, while in the original study the difference between diabetes, obesity, previous antihypertensive therapy and
both groups was lower (56.7% and 44.8%, respectively). left ventricular hypertrophy 35. Of all these factors, only
However, both studies showed a lower percentage of age, gender, use of oral hypoglycemic agents and duration
patients with a high degree of adherence, less than 20%. of antihypertensive treatment were considered in this
Initially, the use of the first Morisky adherence scale investigation. Nevertheless, the only variable related to
(MMAS-4) allowed not only to determine non-adherent poor BP control, as well as non-adherence, was the use of
patients at risk of not achieving BP control, but also to three or more antihypertensive agents.
know some causes of poor adherence. As new self-reporting One hypothesis for this finding is that even among
methods were developed, its use as a screening tool in patients considered adherent by the MMAS-8, there
clinical practice has become an increasingly desirable may be incorrect drug use. The translated and validated
characteristic. In the treatment of patients with uncontrolled adherence scale used in this study, although it contains
hypertension, for instance, the investigation of the probable several questions related to specific non-adherent behavior,
causes should always consider the non-adherence. In our does not address issues such as time and method of
study, the translated version of MMAS-8 identified a large using, which may explain the lack of association between
proportion of non-adherent patients among those with the use of three or more antihypertensive drugs with an
uncontrolled blood pressure, more than two-fold the inadequate adherence, but the existence of an association
number of patients with BP under control. between the number of these drugs and lack of BP control.
According to the World Health Organization, 51% of Another hypothesis is the highest degree of severity of these
patients with hypertension in the United States adhere to patients clinical condition, implying greater difficulty in
treatment, while in China, the rate of adherence among controlling BP. Moreover, factors such as the quality of
these patients is 43% 3. Hyre et al. 29, in a study with pharmacotherapy practiced within the Public Health System
MMAS-8 applied to patients with hypertension, found that should be investigated for the accurate identification of the
35.6% of patients adhered completely to the prescription. relevant causes of uncontrolled hypertension.
However, in such studies, the cost of drugs was a factor In clinical practice, patients adherent and non-
that hindered patient adherence, whereas the patients responsive to the triple optimized antihypertensive therapy
included in this study had free access to anti-hypertensive that includes a diuretic agent characterize cases of resistant
drugs. The cost of drugs is the most widely studied 8,31 hypertension9-11. According to this concept, 1.8% of the
predictive factor of nonadherence, and its importance interviewed patients had resistant hypertension. The
in the compliance to antihypertensive treatments have prevalence of resistant hypertension, which is generally
been demonstrated in studies involving large numbers of not known, has recently been estimated in the United
patients32,33. Nevertheless, the rate of adherents observed States, representing approximately 8.9 % of hypertensive
in the current investigation was lower than that in the patients36. In this situation it is necessary to evaluate the
aforementioned studies, indicating that free access to presence of factors that hinder BP control, such as excessive
antihypertensive treatment itself did not lead to satisfactory sodium intake, alcohol consumption, obesity, use of drugs
levels of adherence. with potential to raise blood pressure, obstructive sleep
According to two major studies reviewing therapeutic apnea syndrome and secondary forms of hypertension,
adherence, one of which covers fifty years of research and correct these factors9.
on the topic, adherence has no apparent association In turn, the term pseudoresistant hypertension refers
with demographic characteristics - such as gender, age, to the lack of BP control in patients with appropriate
socioeconomic status and ethnic group - and disease treatment exposed to other factors that contribute to raise
severity 2,31 . Some predictors, however, have been BP measurements, such as inappropriate measurement
consistently associated with poor adherence, among which technique, white-coat effect and low adherence10,11. The
we highlight the complexity of the regimen, the treatment choice of the active ingredients or dose, the first of the
of asymptomatic disease, the presence of psychological causes of pseudoresistant hypertension was not analyzed
problems like depression and medication side effects 34. individually in our study, but considered in accordance
Except for the psychological problems, which were not with the antihypertensive and dose ranges contained in
considered in our study, other factors had little or no the National List of Essential Medications (Rename) 37.
influence on the adherent behavior of the studied patients. Thus, no therapeutic choice was considered inappropriate.

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 Oliveira-Filho et al
Medication adherence vs. blood pressure control

Therefore, all patients with uncontrolled BP who did not have Limitations
resistant hypertension were classified as having pseudoresistant In this study, some predictors of non-adherence - such
hypertension, found in 64.1% of the patients. Pseudoresistant as depression - and of absence of blood pressure control
hypertension caused by poor adherence accounted for 58.3% - such as ethnicity and higher basal levels of systolic and
of patients in the study. It is important to consider that this diastolic BP - were not investigated as variables of interest
or even considered in the process of patient inclusion. The
value could be even higher, as the self-reporting methods
classification of patients with uncontrolled hypertension
have as major limitation the underestimation of the number
according to the pseudo-resistant hypertension type is also
of non-adherent individuals. subject to interpretation bias, since despite the careful
In turn, the self-reporting methods to determine adherence, observation of other causal factors of pseudo-resistant
in contrast with techniques such as quantification of drugs and hypertension, and efforts to reduce or control some of them,
such as white-coat effect and inadequate measure of blood
their metabolites in body fluids, drug electronic monitoring
pressure, the only cause that can be determined with precision
(Medication Event Monitoring System - MEMS) or counting was therapy adherence.
the pills unused by the patient, are simple, rapid, noninvasive,
and economical, and can provide a real-time opinion about
Final considerations
the adherence behavior of patients and potential reasons for
The diagnosis of non-adherent behavior through the use
non-adherence38.
of the new 8-item Morisky Medication Adherence Scale
Although these methods are subject to bias, as the (MMAS-8) in patients treated with antihypertensive drugs
overestimation of adherence, the constant improvement was a predictive factor of elevated systolic and diastolic blood
of these instruments and their validation studies in pressure. Considering that non-adherence is a major cause
different populations have increased their adoption in of uncontrolled blood pressure, the use of self-report scales
related to BP is a simple and inexpensive measure to assist the
clinical practice 6.
clinical treatment of patients with hypertension.
The internal consistency measured by Cronbachs alpha
(0.69) was lower than that obtained by Morisky et al.6 in
Acknowledgements
patients with hypertension (0.83), but slightly higher than
We thank the support of Secretaria Municipal de Sade
the internal consistency values observed in studies with scale de Macei; of the multidisciplinary teams of Unidades de
translation into other languages published so far39. According Sade da Famlia; the Health Tutorial Education Program
to Aez et al.40, an alpha value > 0.5 have been considered team of UFAL; Dr. Donald E. Morisky, from the University of
acceptable in questionnaire validation studies, a value which California, Los Angeles (UCLA). We also thank the careful data
was adopted by Al-Qazaz in a cross-cultural adaptation collection performed by pharmacists Cludia C. Nbrega de
Farias Ayres, Fernanda Bertazolli Albieri, Hugo A. Leite Mota
study of the MMAS-8 into Malaysian39. Although a number
Vasconcelos, Mirela Quirino de Almeida, Morgana R. Maciel
of questions showed a lower item-total correlation, as is the Cabral Davino, Natyelle M. Santos Macedo and all the patients
case of questions 3, 4 and 7, it was observed that the removal that participated in this study.
of these questions would not increase the instruments alpha,
which would make the exclusion unjustified, de-characterizing Potential Conflict of Interest
the instrument.
No potential conflict of interest relevant to this article was
In the present study, MMAS-8 showed good potential as reported.
a screening tool in clinical practice to identify non-adherent
patients and those at risk of uncontrolled BP, considering Sources of Funding
the reliability of the translated version, its significance This study was partially funded by Fundao de Apoio
association with the BP control and the SBP and DBP Pessoa do Estado de Alagoas (FAPEAL).
values, its simplicity and validation in other studies with
hypertensive patients. In the SUS context, this scale can Study Association
be an important tool for hypertension control. Another
This article is part of the thesis of doctoral submitted by
broader investigation to determine adherence in patients Alfredo Dias de Oliveira Filho (Ncleo de Ps-graduao em
using antihypertensive drugs supplied free of cost by the Medicina - UFS), from Faculdade de Medicina e Faculdade
government is being carried out. de Cincias Farmacuticas Ribeiro Preto - USP.

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