In 1997, the American Diabetes Association (ADA) defined diabetes mellitus (DM) as a clinical syndrome encompassing different nosological entities. This new concept of diabetic disease was ratified by the World Health Organization (WHO) in 1998.
Its definition indicates that it is a group of metabolic diseases whose common link is hyperglycemia secondary to a deficit in insulin secretion, a defect in its metabolic activity, or both. Insulin is a hormone produced by the pancreas. Its main function is the maintenance of adequate blood glucose values. It allows glucose to be transported into the cells, where it is transformed into energy for muscles and tissues to function. It also allows the cells to store glucose so that it can be used when needed.
Thus, we can distinguish the following types of diabetes:
- DM type 1 (Diabetes Mellitus type 1): in this the Beta cells of the pancreas, which are responsible for producing insulin, are completely destroyed. It usually appears in children, although it can also begin in adolescents and adults. It does not depend on family history and in many cases it appears abruptly. The cells that produce insulin in the pancreas (beta cells) are destroyed by autoantibodies. The factors influencing this process are being investigated, since it is not clearly established.
- Type 2 DM (type 2 DM): arises in adulthood, its incidence increases in older people and is about ten times more frequent than type 1. There is a decrease in the action of insulin, so that even if there is a lot of insulin, it cannot act. In short, there is a “mixed component”: on the one hand, there is less insulin secreted by the pancreas and, on the other hand, this insulin works less well in the tissues (this is what we call “insulin resistance”). The main cause of type 2 DM is obesity, since fat tissue produces certain substances that decrease the sensitivity of insulin receptors. As obesity has grown significantly in Spain, so has this type of diabetes.
- Gestational diabetes mellitus (GDM): diagnosed during the second or third trimester of pregnancy, not existing before gestation.
Patients who debut with diabetes usually develop the so-called “cardinal” symptoms of diabetes, which are “polyuria” (urinating frequently and in large amounts), “polydipsia” (drinking water in large amounts, due to a strong feeling of thirst) and “polyphagia” (constant eating due to a strong feeling of hunger). When performing a basal glycemia (measuring fasting glucose) it is usually elevated. These symptoms may not appear in type 2 diabetes and in type 2 diabetes, basal blood glucose may be normal or slightly above normal values. Type 1 diabetes, which usually appears in children or young adults, is not related to overweight and can begin with a serious situation with metabolic acidosis that requires urgent treatment in a hospital; this is called “diabetic ketoacidosis”.
All obese or overweight patients should be screened for type 2 DM by determining a value called glycosylated hemoglobin (HbA1c). This value (expressed in %) indicates the control of diabetes in the last 3 months. Values equal to or greater than 6.5% HbA1c are diagnostic of DM, regardless of the basal glucose figure.
The ADA recommends routine screening for people over 45 years of age who are overweight or have any other risk factors for heart disease or diabetes, such as a sedentary lifestyle, a family history of type 2 DM or a personal history of gestational diabetes, or blood pressure above 140/90 mm Hg.
There is a situation prior to the development of type 2 DM that is called prediabetes (characterized by basal blood glucose levels that may be normal and HbA1c ≧ 5.8% and less than 6.5%). In this situation, which is prior to the development of type 2 DM, the reduction of overweight can slow down this evolution.
Diagnostic criteria of Diabetes Mellitus
- Fasting plasma glycemia ≧ 126 mg/dl.
- HbA1c (glycosylated hemoglobin) ≧ 6.5%.
- Plasma glycemia at 2 hours after oral glucose overload test ≧ 200 mg/dl.
- Plasma glycemia ≧200 mg/dl in patients with classic symptoms of hyperglycemia or hyperglycemic crisis.
Any of these criteria is sufficient for the diagnosis of DM.
Treatment.
Diet of course is a primordial element, a diet of no more than 1500 kcal daily, free of refined sugars and with an adequate intake of proteins, lipids and carbohydrates. In short, a varied diet, with an important contribution of vegetables, fruit and fiber.
The objective of pharmacological treatment in diabetes is the treatment of hyperglycemia.
Type 1 DM and gestational DM must inevitably be treated with insulin or insulin analogues. Basal insulins are usually combined with rapid insulins.
In type 2 DM, we have a large arsenal of drugs for the treatment of hyperglycemia. Most of the drugs used are oral, and can be used in monotherapy or in combination with other drugs. Other drugs are parenteral such as GLP-1 and are capable of reducing body weight due to their effect on gastric emptying. These latter drugs, together with glucosurics (ISGLT-2), which also reduce weight, have proven cardiovascular protection and nephroprotective effects.
Finally, insulins or insulin analogs can also be used, both basal and rapid or ultra-rapid, which can be combined with oral drugs, especially the former.
In type 2 DM, bariatric surgery (stomach reduction) is indicated in selected cases of diabetes and obesity.
In type 1 DM, pumps with continuous subcutaneous insulin infusion are being used in some cases with great success, since they simulate physiological secretion of this hormone in the body.
Monitoring of diabetes control is based on achieving HbA1c levels as close as possible to 6% or even below this value and baseline blood glucose levels of around 100-120 mg/dl.
Good control of both type 1 and type 2 DM has an impact on the reduction of cardiovascular events (stroke, infarction or peripheral arterial ischemia). It should be taken into account that DM is one of the main cardiovascular risk factors.
In addition, type 2 DM is the main cause of chronic kidney disease in the world that leads to the need for dialysis (hemodialysis or peritoneal dialysis). Poor control of diabetes is directly related to peripheral retinopathy, which is one of the leading causes of blindness in the world. Diabetic neuropathy is a lesion primarily of the peripheral nerves, both motor and sensory, that produces painful symptoms in the extremities, which significantly worsens the quality of life of diabetics.