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).