Diabetes: Biopsychosocial Features Affecting Metabolic Control and Treatment Adherence

Introduction

According to the International Diabetes Federation statistics, the global prevalence of diabetes mellitus recorded in 2017 is 8.8% (95% confidence interval 7.2-11.3%) among adults in the age group 20 – 79 years (IDF, 2017). This is equivalent to 424.9 million of persons with diabetes mellitus globally. By the year 2045, the global prevalence of diabetes mellitus in the 20 – 79 age group is likely to further increase to 9.9% (95% CI 7.5-12.7%); equivalent to 628.6 million persons with diabetes mellitus globally (IDF, 2017; NCD Risk Factor Collaboration, 2016). In an earlier report the global age-standardized prevalence of diabetes mellitus in males increased from 4.3% in 1980 to 9.0% in 2014 in the 20 – 79 age group, and 5.0% to 7.9% in females (IDF, 2017). Further, the IDF Atlas approximates that globally another 352.1 million persons have impaired glucose tolerance (IGT) which is expected to increase to 531.6 million in 2045 (IDF, 2017; NCD Risk Factor Collaboration, 2016).

The prevalence of diabetes mellitus have increased faster in low- and middle-income countries compared with high-income countries with the greatest rise observed in the Eastern Mediterranean Region value of 13.7% (NCD Risk Factor Collaboration, 2016). The increase in prevalence of diabetes mellitus is due to a number of factors such as growth in population, ageing, and increased global obesity (Seshasai et al., 2011).

Diabetes mellitus has been recognized as a heterogeneous disorder associated with varying etiology and clinical manifestations. It encompasses pathogenic processes such as insulin deficiency attributable to autoimmune attack of pancreatic beta-cells, impaired insulin secretion and insulin resistance. The diagnostic classification of the disease is largely dependent on glycemic thresholds associated with microvascular complications (Punthakee et al., 2018). There are two main categories of diabetes: type 1 and type 2 diabetes mellitus.

Type 1diabetes mellitus is one of the most prevalent childhood diseases, although it can affect individuals across different age ranges. It encompasses T-cell mediated destruction of insulin producing pancreatic beta-cells resulting in deficient beta-cell mass, insulin deficiency and elevated blood glucose levels (Punthakee et al., 2018). The disease is also characterized by impaired pancreatic alpha-cell function and elevated peripheral glucagon which exacerbates the metabolic complications of insulin resistance (Ozougwu et al., 2013). Genetic, immunologic and environmental factors are the main etiological forces driving the disease (Mouri and Badireddy, 2019).

Type 2 diabetes mellitus is a progressive polygenic disorder characterized by diminished beta-cell insulin secretory capacity and impaired target tissue response to insulin (Lee and Halter, 2017). As such, insulin resistance and impaired beta-cell function are hallmarks of the disease. Type 2 diabetes mellitus often accounts for an estimated 90% of all diabetes cases and is typically manifested at later stages in life, even though there is evidence of increased occurrence in younger age groups (Bansal et al., 2017). It is well established that many genetic variants increase the risk for type 2 diabetes mellitus.