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.