5.4.1 Introduction

Diabetes mellitus is a chronic disease, characterised by hyperglycaemia, resulting from defects in the insulin secretion, insulin action or in both insulin secretion and action. This may lead to persisting hyperglycaemia, followed by long-term damage and failure of different organs, especially eyes, kidneys, blood vessels, nerves and heart. Microvascular complications (diabetic retinopathy, nephropathy and neuropathy) and in particular cardiovascular disease contribute to high morbidity and mortality.

Diagnosis of diabetes according to the WHO is based on symptoms including polyuria, polydipsia and unexplained weight loss and /or a hyperglycaemia ≥ 11.1 mmol/l (200mg/dl) in a random sample or a fasting plasma sample ≥ 7.0 mmol/l (126 mg/dl) and /or a postprandial value ≥ 11.1 mmol/l. (Report WHO/IDF 2006). Two major subgroups of diabetes mellitus are currently recognised, representing the majority of the diabetic population:

·Type 1 diabetes mellitus (T1DM) or Immune mediated, juvenile is characterised by a cellular mediated destruction of the pancreatic beta cells. This form, which usually develops before the age of 40, and often in the teenage years, is inevitably linked to an absolute deficiency of insulin that must be restored to safeguard patients' survival. Symptoms rapidly developing with the progression of the disease include an excessive excretion of urine, thirst, constant hunger, weight loss, vision changes and fatigue. Environmental factors combined with a genetic predisposition are involved in this process. A percentage of about 10% of the diabetic population is affected by the disease, with a worldwide increase in incidence being consistently reported over the last 30 years.

·Type 2 diabetes mellitus (T2DM) or non-insulin dependant, is initially characterised by insulin resistance and relative insulin deficiency. With time, it may modify to a predominantly secretion defect of the beta cells and insulin deficiency. Symptoms may be similar to those of T1DM, but less apparent; the disease is diagnosed later, when the occurrence of major complications is more difficult to avoid.T2DM is potentially preventable through control of overweight and obesity. With the increase of people of all age groups suffering from overweight and obesity, the prevalence of T2DM is increasing in most countries worldwide (King 1998; Wild 2004). In the past, this form of diabetes was considered to occur mainly in the elderly population over the age of 40. Because of the increased prevalence of obesity, the onset of the disease has become more frequent at a much younger age. As an average, nine out of ten people with diabetes have type 2 diabetes and over 80% of these people are overweight.

Worldwide estimates of prevalence of diabetes are scarce and not accurate.

The most complete resource in the field is the IDF Atlas, whose third edition (IDF Atlas, 2006) reports 246 millions currently affected, equivalent to a global prevalence of about 6.0%, 46% of which in the 40-59 age group, with a projection of 380 millions (7.3%) forecast for 2025. According to the report, almost 80% of the total diabetic population resides in developing countries. The regions with the highest rates are the Eastern Mediterranean and Middle East, where 9.2 % of the adult population are affected, and North America (8.4%). The highest numbers are found in the Western Pacific, where some 67 million people have diabetes, followed by Europe with 53 million. India leads the global top ten in terms of the highest number of people with diabetes with a current figure of 40.9 million, followed by China with 39.8 million, USA, Russia, Germany, Japan, Pakistan, Brazil, Mexico and Egypt. Developing countries account for seven of the world’s top.

The situation in Europe is among the most alarming. According to WHO, diabetes prevalence in the European Region is around 7.8% (about 48 million people), with an expected 21 %  increase  to 9.1% (about 58.6 million people) over the next 20 years. (Figure 5.4.1). The latest edition of the IDF Atlas reports a prevalence of 8.5% in the EU 27 Member States, equivalent to an increase of 1.0% in only 3 years. Very important differences in prevalence are observed among the different EU Member States. Germany and Austria have the largest prevalence rates with 11.8% and 11.1%, while the UK is the country with the lowest rate, at 4%. New Member States in general experience prevalence rates above 10%. Diabetes mellitus has been recognised on a worldwide scale to be one of the major contributors to economic and human burden, equally in the developed and developing countries (King 1998; Wild 2004).

Figure 5.4.1. The Growing Diabetes Epidemic

(WHO Report, 6 May, 2004)

A complex interaction of genetic, social and environmental factors leads to the increased prevalence of type 2 diabetes. For low and middle-income countries, economic development leads to very rapid changes in lifestyle, diet and physical activity regardless of weight gains. In the developed world, diabetes is most common among the poorest communities: deprivation, lack of sanitation, and low cost food constitute a threatening basis for the onset of the disease. People of working age are mostly involved in the process.

Differences in the possibility to ensure an early diagnosis are influenced by socio economic, geographic and ethnic differences. (Smith, 2007; Dyhr, 2007; Diaz, 2007). Specific individual characteristics have been consistently found by a range of epidemiological studies to be highly significant risk factors that can be usefully targeted as indicators of the development of diabetes. Among the potential factors, impaired glucose tolerance (IGT) is strongly associated to the occurrence of the disease, leading about 10% of those affected to develop diabetes in one year. For IGT, the IDF reports a staggering worldwide prevalence of 7.5%, estimated to increase up to 8.0% in 2025.

Another important aspect in diabetes is the one involving costs. The CODE-2 study has measured the health care costs of people with type 2 diabetes in 8 EU countries: Belgium, France, Germany, Italy, the Netherlands, Spain, Sweden and the UK (Jonsson et al 2002). For these 8 countries, the average annual costs per patient with type 2 diabetes were estimated at €2,834 in 1999. The health care costs of diabetes as a percentage of the total healthcare expenditures ranged from 1.6% in the Netherlands to 6.6 % in Italy. Hospitalisations accounted for the greatest proportion of costs (55%). A Swedish study (Jonsson et al 2000) observed that the cost profile during the natural history of diabetes is 'U' or 'J' shaped with relatively high costs immediately after diagnosis, followed by a fall and again a rise with the onset of complications. Indirect costs by diabetes due to loss of productivity may be as great or even greater than direct health care costs (WHO 2002). Unfortunately, information on overall costs of diabetes is not collected continuously; this because this data is difficult to collect due to the different and fragmented accounting systems. Thus, data mostly relies on the conduction of ad hoc studies that are often limited in terms of geographical representation.

Severe long term complications are observed in both forms of diabetes. Type 2 diabetes tends to be associated with hypertension, (high blood pressure) and increased blood levels of total cholesterol and triglycerides. High blood sugar levels (hyperglycaemia), hypertension and the change in lipids levels are implicated in the increased risk of complications, affecting both small blood vessels (macro-vascular complications including vision loss, nerve and kidney damage), and larger blood vessels (macro-vascular complications such as myocardial infarction and stroke). Long duration of hyperglycaemia in type 1 diabetes represents also a well known major risk factor for blood vessel changes. Near normalisation of blood glucose values as well as lipid levels and blood pressure are necessary to prevent and/or reduce such complications.

Main complications of diabetes are as follows:

Feet: blood flow problems can cause nerve damage in the hands and feet. Because of abnormal sensation (nerve function) or blood flow, people with diabetes may develop foot ulcers. In some situations, this may lead to amputations;

Eyes: blood flow problems can also interfere with the blood supply to the retina, leading to visual disturbance and blindness (retinopathy). High blood sugars, may also induce cataract possibly leading to blindness;

Kidneys: Over time, high blood glucose can cause damage to the small blood vessels in the kidneys, affecting their filtering ability and thus leading to kidney failure (necessitating renal replacement therapy: dialysis or transplantation);

Impotence: On average, more than 30% of men with diabetes report erectile dysfunction/ impotence; this percentage increases substantially with diabetes duration and age;

Pregnancy: Pregnant women with uncontrolled diabetes are at an increased risk of miscarriage and stillbirth.

Cardiovascular complications: Long lasting hyperglycaemia as well as abnormal lipid profiles will cause macrovascular modifications leading to myocardial infarction or stroke. 

Diabetes is recognised as a top policy priority by Member States of the European Union. More effective solutions need to be developed for the prevention, diagnosis and treatment of diabetes at national and EU level. As for many other chronic diseases, an adequate self-management is the key for a considerable improvement of the quality of life and patients' outcomes on an everyday basis. The provision of adequate information for end users is fundamental to empower patients and involve them in reducing the gap between research and practice.