Discussion
As described at the beginning in this scoping review, medication nonadherence is a problem affects the health care system, healthcare professionals, and patients. So, to the best of our knowledge, this is the first scoping review that summarize and identify medication adherence rate, types of measurement methods, factors of nonadherence to medication, and types of medication adherence enhancing interventions among patients with MDD. Our findings provided many insights into the importance to focus on the prevalence of adherence, factors affect to adherence, and interventions to improve adherence in patients with MDD. Also, attention and expand the body of knowledge towards medication adherence in MDD facilitates healthcare organizations, policymakers, professions, and researcher in the design and implementation of medication adherence enhancing strategies.
This scoping review included 36 in the past 5 years met our eligibility criteria, selected by using selection process of PRISMA-ScR guidelines.42 The authors attempted to adjust the need to lessen the heterogeneity of selected studies for the one hand while assuring the fitting impression of valid practice on the other. Consequently, the main results divided according to the research questions. In the identified articles, the current authors noted that the quality of the most included studies was generally good, except for one study by Shrestha Manandhar et al60 which yielded the lowest score (25%) using MMAT. The authors identified the prevalence of medication adherence are range from 10.6% to 85.4%, and the rate of medication adherence in majority of studies are low (<60%).21-23,25,46,48,52,53,55,56-58,60,63-71
Concerning the variation of adherence rate, the current authors were unable to standardize the adherence rates related to the variation in study designs, adherence measures, and inconsistent definitions of medication adherence were associated with unacceptable heterogeneity. Regarding the adherence measures, researchers used various methods in an attempt to assess patient adherence to medication, but none of them can be considered universally accepted ”gold Standard” for measuring adherence. The majority of studies in this scoping review used indirect measures such as self-reported questionnaires and pharmacy refill data. This is because direct methods such as biological measures are not always acceptable, appropriate, feasible, or cost-effective.18 This view potentially explains that most studies (22) measuring adherence based on self-report as subjective measurements, there were 12 different measures. Also, nine studies used objective measurements by using the electronic data records and two studies used pill count. Although, views as to the best measurements vary, each is acknowledged to have its advantages and limitations. The advantages of indirect measures in these studies are flexible, easy to administer, relative unobtrusiveness, inexpensive, and time-saving to complete. However, limitations may be subject to bias (e.g., refill prescription is different to ingestion of medication), social desirability, and overestimate adherence.19,25,47,53-55,57,58,69,70,72
However, 26 of included studies investigated the factors that influence medication adherence among patients with MDD. This scoping review identifies multi-factorial causes leading to poor medication adherence, which classified as WHO into five categories: socioeconomic, healthcare provider/system, illness, medication, and patient-related factors.3 This scoping review recognizes illness, medication, and patient-related factors were the most factors associated with medication adherence. This explained that the common factors to adherence are under the patient’s control, which patient’s perspective toward illness and medication maybe is a considered decision by patients making their own choices about taking medications, based on their beliefs, personal conditions, and the information offered to them.
However, various interventions address the aforementioned factors to improve adherence. With an understanding of the factors that influence medication adherence among patients with MDD, proper intervention can then be tailored individually to improve the medication-taking behavior of each patient. Our scoping review identified ten studies that used a range of counseling, education and information, reminders, monitor feedback, and multi-faceted intervention to improve medication adherence among patients with MDD. These interventions implemented by many different health care workers who have an essential role in improving adherence because they can influence one or more of the factors that determine adherence.
The number of studies with either positive or no effects. The most common interventions targeting healthcare provider/system and patient-related factors were evident such as Aljumah & Hassali47, Isa et al54, Sirey et al19, Taleban et al61, and Vannachavee et al62. The present review showed that a single-element intervention might be expected to have been less effective on medication adherence.47,61,68,71 However, there is no universal intervention that is suitable for all nonadherent patients. In this scoping review, multi-faceted intervention is most interventions used in 6 included studies. In addition, the six studies presented a significant result about improving medication adherence. Nieuwlaat et al32 noted that effective intervention is complex, involves several components to address a multi-factorial approach that effect on medication adherence.
However, healthcare professionals play an essential role in assessing patients with nonadherence and delivering appropriate interventions to support and improve adherence, persistence, and retention in medication and care. Also, nurses play a key role in screening, assessing, and promoting medication adherence.