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ORIGINAL ARTICLE
Identification of psychosocial factors of
noncompliance in hypertensive patients
NB Hassan
1
, CI Hasanah
2
, K Foong
3
, L Naing
4
, R Awang
5
, SB Ismail
6
, A Ishak
6
, LH Yaacob
6
,
MY Harmy
6
, AH Daud
6
, MH Shaharom
7
, R Conroy
8
and ARA Rahman
9
1
Department of Pharmacy, Hospital Universiti Sains Malaysia & Department of Pharmacology, Universiti
Sains Malaysia, Kubang Kerian, Kelantan, Malaysia;
2
Department of Psychiatry, School of Medical Sciences,
Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia;
3
National Drug & Doping Center, Universiti
Sains Malaysia, Pulau Pinang, Malaysia;
4
School of Dental Sciences, Universiti Sains Malaysia, Kubang
Kerian, Kelantan, Malaysia;
5
National Poison Center, Universiti Sains Malaysia, Pulau Pinang, Malaysia;
6
Department of Family Medicine, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian,
Kelantan, Malaysia;
7
Department of Psychiatry, School of Medical Sciences, Universiti Kebangsaan Malaysia,
Malaysia;
8
Department of Epidemiology & Public Health Medicine, Royal College of Surgeons, Dublin,
Ireland and
9
Advanced Medical and Dental Institute, Universiti Sains Malaysia, Pulau Pinang, Malaysia
This cross-sectional study was aimed to identify the
predictors of medication noncompliance in hyperten-
sive patients. The study was conducted at the Family
Medicine Clinic, Hospital Universiti Sains Malaysia,
Kelantan, Malaysia, which is a university-based teaching
hospital. All hypertensive patients aged 40 or over-
registered from January to June 2004, who had been on
treatment for at least 3 months, were screened. Pre-
viously validated self-administered questionnaires were
used to assess the compliance and psychosocial
factors. A total of 240 hypertensive patients were
recruited in the study. Of these, 55.8% were noncom-
pliant to medication. Logistic regression showed that
age (adjusted odds ratio (OR): 0.96; 95% confidence
interval (CI): 0.92–0.997; P: 0.035), patient satisfaction
(adjusted OR: 0.97; 95% CI: 0.93–0.998; P: 0.036) and
medication barrier (adjusted OR: 0.95; 95% CI: 0.91–
0.987; P: 0.009) were significant predictors of medica-
tion noncompliance. Therefore, younger age, poor
patient satisfaction and medication barrier were identi-
fied as independent psychosocial predictors of medica-
tion noncompliant in hypertensive patients.
Journal of Human Hypertension (2006) 20, 23–29. doi:10.1038/
sj.jhh.1001930; published online 22 September 2005
Keywords:
medication noncompliance; psychosocial factors; patient satisfaction
Introduction
Blood pressure (BP) is a major risk factor for
developing coronary heart disease, stroke and con-
gestive heart failure. He and MacGregor,
1
in a meta-
analysis study, demonstrated that 125 600 events
(nonfatal stroke or ischaemic heart disease) could be
prevented each year in the UK if all UK hyperten-
sives reduced their systolic BP to o140 mmHg. The
primary goal in treating hypertension is to achieve
optimal BP levels, thereby reducing the risks of
cardiovascular morbidity and mortality.
2,3
However,
despite the expanding choices in antihypertensive
treatments, less than one-third of hypertensive
adults have their BP adequately controlled in the
United States.
4
In Malaysia, the Second National Health Morbid-
ity Survey reported that the prevalence of hyperten-
sion among adults aged 30 years and above was
29.9%, of whom 32.6% had stopped treatment since
diagnosis. The main reasons given for noncompli-
ance are predominantly based around poor com-
munication. These include the perception that
hypertension was not a serious illness, the patient
had been cured or that treatment was no longer
required.
5
Another Malaysian study has shown that
the commonest cause of resistant hypertension
requiring admission is noncompliance.
6
Compliance describes the extent to which a
person’s behaviour coincided with medical ad-
vice.
7,8
Compliance has been evaluated from a wide
range of scientific and clinical perspectives since
the 1950s. Compliant patients are defined as those
who accept their physician’s advice to start drug
therapy and who take their medication at least 80%
of the time.
9,10
Noncompliance means constant
Received 20 June 2005; revised 11 July 2005; accepted 12 July
2005; published online 22 September 2005
Correspondence: NB Hassan, Department of Pharmacy, Hospital
Universiti Sains Malaysia & Department of Pharmacology, School
of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian,
16150, Kelantan, Malaysia.
E-mail: norul@kb.usm.my or norul.badriah.hassan@h.usm.my
Journal of Human Hypertension (2006) 20, 23–29
&
2006 Nature Publishing Group All rights reserved 0950-9240/06
$30.00
www.nature.com/jhh
neglect rather than just temporary forgetfulness or
neglect of treatment.
3
Medication noncompliance is a serious healthcare
concern and has provided challenges to the health-
care providers.
11
However, despite considerable
effort to improve patient compliance, noncompli-
ance continues to be a significant problem.
12,13
When medications are used incorrectly or not taken
at all, healthcare providers’ time, effort and exper-
tise are wasted. Furthermore, noncompliance may
impair patients’ quality of life, make the condition
more difficult to treat, may cause further complica-
tions such as cardiovascular and renal diseases and
a financial strain to health management.
14–16
Psychosocial factors related to noncompliance are
well-recognized problems, and have been documen-
ted in literature with mixed results. Studies have
suggested that age,
17,18
sex,
18
lower socioeconomic
status, severity of disease,
17
drug choice,
7,19,20
num-
ber of medications prescribed,
18,19
drug tolerabil-
ity,
7,20
regimen complexity,
18,20
co-morbid medical
conditions,
17,19
family support,
21
self-efficacy, inten-
tion to comply,
22
physician–patient relationship,
23
satisfaction with health care
24
and depression
25,26
are associated with compliance. However, some of
these studies are limited by specific race,
17,24
usage
of nonvalidated tools,
22
and failure to exclude newly
diagnosed patients and patients with co-existing
medical illnesses.
23
Factors contributing to noncompliance may vary
from country to country and may contribute to the
variations of the results in the published studies.
Furthermore, compliance is a dynamic phenomenon
and its degree may vary over time. Hence, identifi-
cation of factors contributing to noncompliance is
very critical for effective planning and performing
intervention strategies. Hypertension is the disease
in which compliance and persistence have been best
studied,
18
and it served as a model in our study. It is
the objective of the study to identify psychosocial
predictors of medication noncompliance in hyper-
tensive patients using valid and reliable question-
naires.
Materials and methods
All patients registered at the Family Medicine
Clinic, Hospital Universiti Sains Malaysia, Kelan-
tan, Malaysia, from January to June 2004 were
screened based on medical records. Patients were
eligible for the study if they fulfilled these inclusion
criteria: essential hypertension, on antihypertensive
medication for at least 3 months, aged 40 years old
and above, on at least one antihypertensive medica-
tion and not more than three antihypertensive
medications, and agreed to participate in the study.
Patients were excluded if they were pregnant, had
secondary hypertension, renal impairment, im-
paired liver function, other concomitant diseases
such as diabetes mellitus, ischaemic heart disease,
congestive cardiac failure, cerebro-vascular acci-
dent, bronchial asthma, chronic obstructive pul-
monary disease and BP of 200/120 mmHg or more.
Eligible patients were asked basic information of
their illness to confirm their fitness for the study.
Patients who agreed to participate were given
information about the study and asked to sign
consent forms. Patients were then given validated
compliance questionnaire and psychosocial ques-
tionnaire to complete while they were waiting to
see their doctors. Questionnaires typically took
15–40 min to complete. Patients who had difficulty
in reading were assisted in completing the ques-
tionnaire. This study was approved by the Univer-
siti Sains Malaysia Research and Ethical Committee
on March 2003.
Compliance assessment
The compliance questionnaire was developed and
validated in two separate pilot studies of 60 patients
each. The questionnaire consisted of two domains:
a drug-taking behaviour domain comprising seven
items and drug-stopping behaviour domain com-
prising three items. Internal consistency reliabilities
(Cronbach’s alpha) were 0.67 and 0.84, and test–
retest single measure intraclass correlation coeffi-
cients were 0.78 and 0.93, respectively, for each
domain. Possible scores on the scale ranged from
1 to 5, with 1 indicating ‘never’ and 5 indicating
‘very frequent’. All negatively worded scores were
reversed and all scores were converted to a 0 to 100
scale. Patients were categorized as ‘compliant’ if
they had an individual score of 75% or greater,
27
which corresponded to being compliant ‘frequently’
and ‘very frequently’ for all the items in the
questionnaire.
Psychosocial assessment
The psychosocial questionnaire consisted of 35
items in eight psychosocial domains: lifestyle,
emotional state, attitude, understanding, motiva-
tion, perception of susceptibility, perception of
severity, and barriers to compliance. The question-
naire was developed and validated in two separate
pilot studies of 60 patients each. The Health Belief
model and its modified version,
27,28
which were
widely used to study patients’ responses to symp-
toms and their behaviour in response to diagnosed
illness, particularly compliance with medical regi-
mens, were mainly used in the development of the
questionnaire. Cronbach’s alpha ranged from 0.42
(patient barrier) to 0.87 (emotional state), and the
test–retest single measure intraclass correlation
coefficient was 0.53 (communication barrier) to
0.77 (perception of severity). The questionnaire
was scored using a 5-point Likert scale from 1
(never, extremely do not believe, very untrue) to 5
(very frequent, extremely believe, very true). Scores
were obtained by reversing the negatively worded
items on each domain, computing total scores for
Noncompliance in hypertensive patients
NB Hassan et al
24
Journal of Human Hypertension
each domain, and computing and transforming the
raw total scores to a 0 to 100 scales.
A lifestyle score was calculated based on assess-
ment of the participants’ exercise, diet and smoking
habits. Alcohol intake was not included in the
assessment since the majority of patients (97.5%) in
the study did not take alcohol. Emotional state score
was measured as reported frequency of depression,
anxiety and stress within the past 3 months.
Attitude items measured patients’ confidence with
the doctor’s capability, how patients liked the doctor
and whether patients liked taking their medication.
Understanding referred to the patients’ perception
of the cause of hypertension, and information given
by doctors and pharmacists. Motivation assessed
whether patients were tired of continuing their
medication, liked coming to clinic/hospital, were
influenced by families/friends not to take their
medications and whether patients were angry with
the treating doctors. Perception of susceptibility
assessed patients’ perception of the possible causes
of hypertension. Perception of severity addressed
patients’ perception that their medication would
interact adversely with traditional medicines they
were taking or with food. Barriers to compliance
were divided into four subdomains: medication
barrier, patient barrier, communication barrier, and
logistic and transportation barrier. Higher scores in
these domains revealed healthier lifestyle, better
emotional state, more positive attitude, better under-
standing, greater motivation, higher perception of
susceptibility, higher perception of severity or lesser
barriers.
Patient satisfaction was evaluated separately
using Patient Satisfaction with Health Care (PSHC)
Questionnaire, which was developed and validated
in two separate pilot studies. The PSHC question-
naire comprised of four domains, which consist
of overall patient satisfaction, satisfaction with
appointment, satisfaction with doctor service and
satisfaction with pharmacy service. Items were
scored using a 5-point Likert scale from 1 (very
dissatisfied) to 5 (very satisfied). The internal
consistency reliabilities ranged from 0.76 (satisfac-
tion with appointment) to 0.91 (satisfaction with
pharmacy), and test–retest single measure intraclass
correlation coefficients ranged from 0.54 (satisfac-
tion with appointment) to 0.70 (satisfaction with
pharmacy). Scores were obtained by reversing the
negatively worded items on each domain, comput-
ing total scores for each domain, and computing and
transforming the raw total scores to a 0 to 100 scale.
Higher scores indicated greater satisfaction.
Statistical analysis
Demographic data are presented as percentages and
means with standard deviations (s.d.). Associations
between noncompliance and other factors were first
examined using univariate logistic regression meth-
od. Then, multiple logistic regression analysis was
conducted to determine the independent associa-
tions between noncompliance and independent
variables. The selection of variables to include in
the multiple logistic regression model was based on
results from the simple regression method, clinical
importance and results found in literature, and
stepwise variable selection methods were applied.
The most relevant results were adjusted odds ratios
(ORs) of medication noncompliance for different
independent variables with 95% confidence inter-
vals (CIs). All P-values were two-tailed, and Po0.05
was considered statistically significant. Analyses
were performed using SPSS statistical software
version 11 (SPSS Inc., Richmond, CA, USA).
Results
A total of 246 hypertensive patients were eligible
for the study, and 242 (98%) patients agreed to
participate. Among them, 240 (99%) completed the
questionnaires. The majority of the participants
Table 1 Demographic characteristic of study sample
Variable n Frequency
(%)
Mean s.d.
Gender
Male 120 50.2
Female 119 49.8
Age (years) 236 54.5 8.49
Height (m) 230 1.6 0.68
Weight (kg) 230 66.9 11.40
BMI 229 26.5 4.17
Race
Malay 210 87.9
Chinese 28 11.7
Others 1 0.4
Marital status
Married 220 92.8
Single 2 0.8
Divorced 15 6.3
Household income
Low oRM 450.00 39 16.9
Medium RM 450.00–1500.00 106 45.9
High 4RM 1500.00 86 37.2
Formal education
Primary education and lower 61 25.9
Secondary education 43 60.6
Tertiary education 32 13.6
Smoking
Yes 35 14.7
No 204 85.4
Alcohol ingestion
Yes 6 2.5
No 233 97.5
Duration of hypertension in
months
223 98.2 76
Noncompliance in hypertensive patients
NB Hassan et al
25
Journal of Human Hypertension
Table 2 Predictors associated with noncompliance (simple and multiple logistic regression analysis)
Simple logistic regression Multiple logistic regression
Independent variable Crude OR
(95% CI)
P-value
a
Adjusted OR
(95% CI)
P-value
a
Age (years) 0.96 (0.93, 0.99) 0.012 0.96 (0.92, 0.997) 0.035
Gender
Male 1.00
Female 1.26 (0.76, 2.10) 0.371
Race
Malay 1.00
Others 1.23 (0.57, 2.83) 0.566
BMI
0.96 (0.90, 1.02) 0.227
Marital status
Married 1.00
Unmarried 0.70 (0.26, 1.87) 0.471
Household income
Low oRM 450.00 1.00
Medium RM 450.00–1500.00 1.12 (0.53, 2.40) 0.764
High 4RM 1500.00 1.30 (0.60, 2.85) 0.507
Education
Primary education and lower 1.00
Secondary education 1.30 (0.71, 2.36) 0.398
Tertiary education 2.07 (0.86, 4.99) 0.106
Duration of hypertension in months 1.00 (0.99, 1.00) 0.132
Systolic BP
140 mmHg and lower 1.00 (0.99, 1.01) 0.968
141 mmHg and higher 1.00
Diastolic BP
90 mmHg and below 1.01 (0.98, 1.04) 0.545
91 mmHg and higher 1.00
Lifestyle score 0.99 (0.97, 1.02) 0.516
Emotional state score 0.99 (0.97, 1.00) 0.152
Attitude score 0.99 (0.97, 1.02) 0.604
Understanding score 1.00 (0.98, 1.03) 0.972
Motivation score 1.00 (0.98, 1.02) 0.960
Perception of susceptibility score 1.01 (0.99, 1.03) 0.287
Perception of severity score 0.99 (0.98, 1.01) 0.216
Patient satisfaction
(I) Overall satisfaction score 0.97 (0.95, 1.00) 0.056 0.97 (0.93, 0.998) 0.036
(II) Satisfaction with appointment score 0.98 (0.96, 1.00) 0.096
(III) Satisfaction with doctor score 0.99 (0.96, 1.01) 0.321
(IV) Satisfaction with pharmacy score 1.00 (0.97, 1.02) 0.765
Barriers to compliance
(I) Medication barrier
(a) Taste and smell score 0.99 (0.97, 1.00) 0.100
(b) Colour, brand name, size, and adverse
drug reaction score
0.98 (0.96, 1.01) 0.131
(c) Complex regime, cost, and effectiveness score 0.96 (0.93, 0.99) 0.014 0.95 (0.91, 0.99) 0.009
(II) Patient barrier score 0.99 (0.98, 1.01) 0.371
(III) Communication barrier score 0.99 (0.98, 1.01) 0.416
(IV) Logistic and transportation barrier score 1.01 (1.00, 1.03) 0.122
Dependent variables: compliance (0 ¼ compliance, 1 ¼ noncompliance).
a
LR test.
Noncompliance in hypertensive patients
NB Hassan et al
26
Journal of Human Hypertension
(88%) were Malay, married, with the mean age of 55
years (s.d. 8.5), and there were equal number of men
and women. The medication noncompliance rate
was 55.8%. The characteristics of the participants
are shown in Table 1.
Multiple regression analysis (Table 2) indicated
that noncompliance was associated with age (adjus-
ted OR: 0.96; 95% CI: 0.92–0.997; P: 0.035), overall
patient satisfaction (adjusted OR: 0.97; 95% CI:
0.93–0.998; P: 0.036) and medication barrier: com-
plex regime, cost, effectiveness (adjusted OR: 0.95;
95% CI: 0.91–0.987; P: 0.009). There was no asso-
ciation between noncompliance and other socio-
demographic variables, lifestyle, emotional state,
attitude, understanding, motivation, perception of
susceptibility and perception of severity. For the
model tested, there was no evidence on interaction
among the independent variables.
Discussion
Poor medication compliance was frequent in our
hypertensive patients and the overall noncompli-
ance rate measured in our study was consistent with
other studies.
10,29–33
Iskedjian et al.
30
in a meta-
analysis study reported that rates of compliance to
pharmacotherapy ranged from o5% to 490%. Aziz
and Ibrahim,
31
in a previous Malaysian study,
reported 56% noncompliance in patients with
chronic diseases such as hypertension, ischaemic
heart disease, diabetes and bronchial asthma. In
another study, Supramaniam
32
found that more than
59% of hypertensive patients did not adhere to the
medications prescribed.
Predictors of noncompliance identified from our
study were age, overall patient satisfaction and
medication barrier (complex regime, cost, effective-
ness). These results were inconsistent with the
findings from another local study which found that
none of these variables were significantly related to
compliance, except adequacy of BP control.
34
How-
ever, a structured interview was utilized with no
information given on inter-rater and intra-rater
reliability of the questionnaire.
In agreement with Bloom,
18
age was found to be
significantly and independently associated with
noncompliance. Compliance with antihypertensive
drugs was better in older hypertensive patients.
Our study confirmed previous findings (Tables 3,
4), demonstrating that poor PSHC was significantly
and independently associated with poor medication
compliance.
24,35
Renzi et al.
35
reported that treat-
ment adherence was strongly associated with com-
plete satisfaction in dermatologic patients. However,
Wang et al.
25
found no association between PSHC
and compliance.
Medication barrier, which was represented by
complex regime, cost, and effectiveness, were found
to be inversely associated with compliance and this
result was consistent with other findings.
18–20
Monane et al.,
19
in a retrospective study of 8643
hypertensives, found that good compliance was
inversely correlated with the use of multiple drugs
and the number of medications prescribed.
Wang et al.
25
found significant association bet-
ween depression and noncompliance in hyperten-
sives. Although this study demonstrated depression
as a multivariate predictor of noncompliance, this
was not confirmed in our study. The lack of
correlation between emotional state and noncom-
pliance in our study may be related to the homo-
genous nature of our study population. Newly
diagnosed patients and patients with other conco-
mitant diseases including depression were excluded
from our study. This inconsistency might also be
due to different setting, time and measurement tools
used in the study.
The findings of this study have several limita-
tions. Self-reporting was used as the only measure of
compliance, and this may lead to overestimation.
36
Lim et al.
34
reported only 71% sensitivity and 50%
specificity of self-report as a measure of compliance
when compared with pill count. A combination of
self-report and objective measures may yield a
higher accuracy concerning compliance behaviours.
The use of objective measures like pill counts,
serum bioassays and BP controls in conjunction
with self-report should be explored in future
compliance studies.
Furthermore, the cross-sectional design used in
the study might not capture the compliance rates
accurately. The best method for evaluating compliance
in hypertensive patients is long-term observation.
3
Table 3 Current concepts in compliance
K Compliance is a dynamic phenomenon and its degree may
vary over time, place and population.
K Psychosocial factors related to noncompliance are well-
recognized problems and have been documented in literature,
but with mixed results.
K Studies have suggested that age, sex, lower socioeconomic
status, severity of disease, drug choice, number of medication
prescribed, drug tolerability, regimen complexity, co-morbid
medical conditions, family support, self efficacy, intention to
comply, physician–patient relationship, satisfaction with
health care and depression are associated with compliance.
K However, some of these studies are limited by specific race,
usage of nonvalidated tools and failure to exclude newly
diagnosed patients and patients with co-existing medical
illnesses.
Table 4 What this study adds
K Identified psychosocial predictors of medication
noncompliance in hypertensive patients using valid and
reliable questionnaires.
K Study population is a highly homogenous sample and
controlled for the presence of concomitant diseases, number
of medication and severity of hypertension.
K Patient satisfaction, age and medication barrier have been
identified as predictors for medication noncompliance in our
population.
Noncompliance in hypertensive patients
NB Hassan et al
27
Journal of Human Hypertension
Cohort studies with more frequent follow-ups and
larger sample size might yield a more reliable result
since other researchers found that medication non-
compliance worsened over time.
37,38
In conclusion, younger age, poor patient satisfac-
tion and medication barrier (complex regime, cost,
effectiveness) were identified as psychosocial pre-
dictors of medication noncompliance in hyperten-
sive patients. Identification of multiple factors that
predict noncompliance will allow healthcare provi-
ders to plan and implement various intervention
strategies to improve medication compliance.
Acknowledgements
This study is supported by a grant from the
Intensification of Research in Priority Area (IRPA),
Ministry of Science, Technology and Innovation,
Malaysia (IRPA 305/PPSP/6140023).
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