Adherence to Therapies in Patients with Type 2 Diabetes

Introduction

The prevalence of type 2 diabetes mellitus is increasing globally and has become a major public health problem. In the USA, a study of 17,306 people over 20 years of age showed that those diagnosed with diabetes increased significantly from 6.5% in the 1999–2002 period to 7.8% in 2003–2006 [1]. In 2011, 366 million people worldwide had diabetes and it is predicted that by 2030, this figure will be 552 million [2]. Diabetes is currently among the top five causes of death in most high-income countries and resulted in 4.6 million deaths globally in 2011. The majority of cases of diabetes mellitus are type 2, and the greatest numbers of people with this disease are aged from 40 to 59 years [2].

The increase in type 2 diabetes is associated with obesity, hypertension, and an increasingly elderly population. Over the last 18 years in the USA, the proportion of adults in the age group 40–74 years with a body mass index ≥30 kg/m² has increased from 28% to 36%, while the proportion undergoing physical activity 12 times a month or more has decreased from 53% to 43%, exacerbating the obesity problem [3]. However, despite strong clinical recommendations for individuals with a history of diabetes to adopt a healthier lifestyle, adherence to improved diet and exercise is poor [3]. Although type 2 diabetes usually occurs in people over the age of 40 years, it is becoming increasingly common in children, adolescents and young adults due to reduced physical activity and unhealthy eating patterns, leading to obesity [4].

The majority of patients with type 2 diabetes fail to control glycemia with diet and exercise and require pharmacotherapy—in general, initially monotherapy with an oral hypoglycemic agents (OHA); however, owing to the progressive nature of the disease, most of the patients will eventually require combination therapy and ultimately injectable treatments as monotherapy or part of polytherapy. Glycemic control in type 2 diabetes is essential to prevent long-term micro- and macrovascular complications [5]. A number of factors other than glycated hemoglobin (HbA_1c) level will influence treatment regimens, and practice guidelines emphasize the need for concomitant treatment of other cardiovascular risk factors, such as arterial hypertension (≥140/80 mmHg) and dyslipidemia [low density lipoprotein (LDL) >2.6 mmol/L; triglycerides...