Abstract
Background: Adherence to medication is the cornerstone to
achieve the best treatment outcome. Pharmacists are healthcare
professionals found in pivotal positions to assess asthmatic patient’s
adherence to medication. A brief, reliable, and valid measure of patient
adherence is useful to enable the pharmacists to deliver that vital
service. This study aims to develop a reliable and valid adherence
assessment tool for asthmatic patients.
Methods : The Adherence to Asthma Medication Questionnaire
(AAMQ-13) was developed based on an extensive literature review,
followed by applying the Delphi technique, and then it was pilot-tested
by 55 patients. The final AAMQ-13 was completed by 213 patients.
Psychometric evaluation was assessed including reliability, criterion
validity, and construct validity.
Results : The AAMQ-13 is a feasible 13 item questionnaire, as it
can be completed within an average of two minutes. It has high internal
validity (Cronbach’s alpha= 0.87). Criterion-concurrent validity was
established by comparing the AAMQ-13 to the Test of the Adherence to
Inhaler (TAI) and the pharmacy refill records. Criterion-convergent
validity was established by comparing the AAMQ-13 to the Asthma Control
Test (ACT) questionnaire and the Positive Health Behaviors Scale (PHBS).
Construct validity was established through AAMQ-13 factor analysis which
revealed two factors explaining 51.76% of the variance.
Conclusion : The AAMQ-13 is a reliable and valid questionnaire
with several desirable characteristics as it has a high internal
validity, good criterion validity, and strong construct validity. The
AAMQ-13 is a suitable questionnaire that can identify non-adherent
patients and reveal the reasons behind their non-adherence (intentional
or unintentional non-adherence).
Keywords: Asthma, Adherence to medication, Compliance,
Questionnaire, Self-report.
Introduction
Asthma is a controllable, but not curable disease affecting patients’
respiratory system. It is characterized by recurrent attacks of
breathlessness and wheezing, which vary in severity and frequency from
patient to patient (1). Over 300 million individuals worldwide live with
asthma (2). The main treatments for asthma are inhalable formulations of
anti-inflammatory medications (preventers) which are needed long-term
and bronchodilators medications (relievers) recommended for relief only
when required (1).
Data from recent studies show that asthma is still a poorly controlled
condition (3). One reason for uncontrolled asthma is patients’
non-adherence to their preventer medications. This has been demonstrated
repeatedly in real-life observational studies published globally during
the previous 15 years; such studies highlight low rates of adherence to
asthma preventer medications ranging between 14% and 50% (4).
Low adherence to inhalers results in poor asthma control, increased
hospitalizations, increased mortality rates, and an increase in costs
(5). Adherence is commonly defined as the degree to which patients
correctly follow medical advices and take their medications in
accordance with the way prescribed by the healthcare team (6).
Experts believe that non-adherence is underpinned by different reasons,
and hence categorize non-adherence into different types. The two main
types include: 1) intentional non-adherence (deliberate non-adherence
which is associated mainly with patient beliefs) and 2) unintentional
non-adherence (unplanned behavior which is mainly associated with lack
of resources) (7,8).
To date, no method has been nominated as a universal gold standard
method for measuring adherence. As objective measures are often costly
or inconvenient; subjective measures such as patient self-reports are
used more frequently in clinical or research settings. Self-report
measures offer several advantages, including low cost, ability to
differentiate between intentional and unintentional non-adherence,
non-invasiveness, flexible to accommodate various conditions, and ease
of administration. If devised well, self-report questionnaires can also
provide valuable information such as the reasons behind non-adherence,
beliefs about medications, and patient understanding of medications
regimens (8–10). A well devised adherence questionnaire should be
reasonably applicable to the patient as they attempt to respond; in the
case of asthma, given inhaled medications are the mainstay of treatment,
the questionnaire should refer to inhaled medications, for example,
also, adherence to when required relievers is not important, hence the
word ‘preventer’ medications is important to specify. These nuances make
generic adherence questionnaires less applicable or relevant to asthma
patients.
Some published questionnaires are long consist of 30 items (11,12), were
developed with relatively small sample size (n= 43-66) (13–16), were
published without a reported sensitivity and specificity (14,17–19),
were published without a reported reliability (15), have a reliability
below 0.7 (13,20), and were only published in English language.
Therefore, there is a clear need for a reliable and valid instrument
that can be used to assess asthma patients’ adherence to preventer
therapy and reasons for non-adherence. Such tools are especially
important for primary healthcare professionals such as pharmacists who
have the opportunity to provide adherence support at the point of
supply.
This study aimed to develop and validate a new self-administrable asthma
adherence assessment questionnaire for use with adult patients. The
purpose of the proposed tool, named as the Adherence to Asthma
Medication Questionnaire (AAMQ-13), is to provide a brief,
patient-friendly method of assessing adult asthma patients’ adherence to
preventer medications in any healthcare setting.