Introduction
Diabetes is one of the leading causes of morbidity and mortality
worldwide. According to the International Diabetes Federation (IDF), 463
million people aged 20-79 years worldwide have diabetes of whom 80%
live in low-and middle-income countries (LMICs). This number is
projected to increase to 700 million by 2045, and most of the rising
burden will occur in LMICs. It is estimated that about half of diabetes
cases in LMICs are undiagnosed or poorly treated1. Diabetes is
associated with an increased risk for a number of serious and sometimes
life-threatening vascular complications, including cardiovascular
diseases (CVDs), diabetic neuropathy, nephropathy and retinopathy. In
fact, CVDs are the most prevalent causes of morbidity and mortality in
people with diabetes.
Achieving diabetes control is the ultimate target to prevent or delay
early complications of diabetes, which depends on adherence to
medications. The World Health Organization (WHO) defines the concept of
adherence to medications as the accomplishment of some behaviour, such
as taking prescribed medications at the right doses and times in the
specified manner as per the recommendation provided by healthcare
providers, followed by a lifestyle modification; otherwise,
non-adherence exists. For people with diabetes, persistent and
compliance with anti-diabetic medication is key to achieving ideal blood
glucose levels. Additionally, suboptimal blood glucose control is
associated with poor adherence or non-adherence to anti-diabetic
medications2,3.
However, in many developed and developing countries, non-adherence to
prescribed anti-diabetic medications remains a serious problem4. Rates of
non-adherence to prescribed anti-diabetic regimens among individuals
with diabetes reportedly ranged from 9% to ˃80%5. The non-adherence
practice may be particularly higher in LMICs where there is poor
accessibility to medicines and healthcare services as well as low level
of awareness about the chronic nature of the disease. Indeed,
non-adherence to medication contributes to substantial worsening of
disease, mortality and increased healthcare cost3. Hence, monitoring of
medication adherence is of great importance to achieve optimal blood
glucose control.
Globally, several screening tools
are available for use to assess medication adherence in individual with
diabetes, such as Morisky Medication Adherence Scale (MMAS-8),
Medication Adherence Rating Scale (MARS), Brief Medication Questionnaire
(BMQ), Self-Efficacy for Appropriate Medication Use Scale (SEAMS) and
Hill-Bone Compliance Scale (HBCS). However only few scales are designed
to assess medication adherence for people with diabetes in LMICs6. Furthermore, studies on adherence to diabetes
medication are being carried out extensively in developed countries and
are scarce in LMICs. The available
evidence in LMICs come from single-center studies using various measures
of adherence. It became necessary and urgently needed to conduct a
systematic review and meta-meta-analysis to understand the burden of and
factors of non-adherence to anti-diabetic medication among individuals
living with diabetes in LMICs, which is crucial in guiding policy-makers
to tailor effective strategies to improve adherence to anti-diabetic
medication, and consequently blood glucose control. This study,
therefore, aimed to summarize available findings of primary studies to
determine the level of anti-diabetic medication non-adherence and
associated factors reported in LMICs.