Discussion
Among the several methods that can be used to assess patients’ adherence
to medications, self-reported questionnaires remain the most convenient
method. We have successfully reached our aim in developing a feasible,
reliable, valid, and patient-friendly method of assessing adult asthma
patients’ adherence to preventer medications in any healthcare setting.
Our current work encompasses the development of and commendable
psychometric properties (reliability, validity, sensitivity, and
specificity) of a newly developed adherence questionnaire, The Adherence
to Asthma Medication Questionnaire (AAMQ-13). Noteworthy, the AAMQ-13
validity was established with a battery of validity tests including
face, content, construct, and criterion (concurrent and convergent)
validity. Moreover, most asthma adherence questionnaires available to
date can only identify non-adherent patients; however, our results
indicate the utility of the AAMQ-13 in gauging reasons underlying poor
adherence. Therefore, we propose that the AAMQ-13 is an instrument that
should have high utility in clinical and research settings. The AAMQ-13
can improve patients with asthma adherence to medications because it
identifies reasons behind non-adherence which will help the healthcare
team and the patient in deciding the
appropriate intervention that should be taken afterward.
The development of the AAMQ-13 followed a stringent series of steps
commencing with a literature review, drafting, three rounds of
re-drafting, and user testing besides the psychometric evaluation. Our
expert panel stated that the appropriate acceptable number of items in
an adherence assessment questionnaire would be from 6 to 25 items. The
AAMQ-13 is perfectly compatible with this present finding, it has 13
items, which makes it a brief questionnaire. Moreover, the most
important driver of the number of items in an instrument is a function
of the number of the domain being measured by the instrument; the
AAMQ-13 was conceptualized with three specific domains; thus, it has a
fairly good balance of items. The number of items in the AAMQ-13 falls
within the range of the published questionnaires; some questionnaire
consists of four items such as the Morisky Medication Adherence Scale
(MMAS-4) and the Brief Adherence Rating Scale (BARS) (16,33), or five
items such as the Adult Asthma Adherence Questionnaire (AAAQ) (34),
while other questionnaires have up to 30 items such as the Drug Attitude
Inventory (DAI) and the Personal Evaluation of Transitions in Treatment
(PETiT) (11,12). The robust process in the development allowed for a
good balance between discriminatory power and respondent/assessor
fatigue. The 13-item solution is well centered as both long
questionnaires and short ones have been reported to be problematic
(35,36). The AAMQ-13 was developed with a good sample size which can be
considered to give a comprehensive and representative data. In
comparison to other published questionnaires; some of them were
developed with a small sample size (n= 43) such as the Brief Medication
Questionnaire (BMQ) (13), in contracts, others were developed with a
relatively large sample size such (n= 1009) as the Test of the Adherence
to Inhalers (TAI) (28).
The AAMMQ-13 has high internal reliability (0.87) that falls within the
range (0.61 in MMAS-4 - 0.93 in DAI) of the Cronbach’s alpha’s of some
published questionnaires (11,33). A high item-item correlation between
item 11 and 12 and to the overall item score indicates the importance of
inhaler use issues as a major factor in adherence. The AAMQ-13 could be
well utilized at the point of inhaler supply in pharmacies. The key to
solve the problem of non-adherence should encourage a ”blame-free”
environment (37). All of the healthcare team should have a vital role in
supporting medication adherence, however, pharmacists can have a unique
one since they interact with almost every outpatient and are the last to
see the patients after they purchase their medications (38). The high
item-total correlation observed in item 4 highlights the importance of
correcting patient’s misbeliefs as many patients stops taking their
medication out of fear of potential side effects. However, chronic
diseases such as asthma are controllable but not curable, and can only
be controlled with patient’s commitment to medications, otherwise, the
frequency and severity of the symptoms may increase. Thus, healthcare
providers should be aware of patient’s beliefs about medication as it
has been previously documented that having a strong beliefs in the
benefits of asthma medication may contribute to better adherence (39).