The term ‘diabetes mellitus’ encompasses a group of diseases which affects almost 200 million people worldwide (type 1 and type 2). This figure is expected to continue rising to more than 330 million by 2030.
In people who do not suffer from diabetes – those with normal glucose tolerance – blood glucose levels are automatically monitored and controlled by the body. This is done by several hormones, including insulin, which is produced by the pancreas.
The pancreas releases insulin after meals to keep glucose in the blood within a normal range. Insulin allows glucose to move from the blood into the liver, muscle and fat cells, where it is used for fuel. Normally glucose levels return to pre-meal levels in two to three hours.
On the other hand, in people who suffer from diabetes or impaired glucose tolerance, the body cannot regulate the amount of glucose in the blood. After eating, diabetics often have long periods of elevated blood glucose levels.
People with diabetes either do not produce enough insulin (type 1 diabetes), or cannot use insulin properly (type 2 diabetes), or both (which occurs with several forms of diabetes). As a result, in diabetic people, glucose in the blood cannot move into the cells and stays in the blood. This causes harm in two ways: cells that need the glucose for fuel have a lack of it, while other organs and tissues are harmed by being exposed to high glucose levels.
Over a long period of time, hyperglycaemia – high blood sugar levels – can cause damage to several organs, including:
• retina of the eye (diabetic retinopathy) which can cause blindness;
• kidneys (diabetic nephropathy) which ultimately causes kidney failure;
• nerves (diabetic neuropathy), which increases risk of foot wounds and ulcers, frequently leading to foot or leg amputations;
• nerves that control the gastrointestinal system, possibly causing chronic diarrohea;
• nerves that control the heart and blood pressure, leading to inability to control heart rate and blood pressure during changes in posture;
• blood vessels, by increasing formation of fatty plaques inside the arteries, thus increasing the risk of heart attacks, stroke and peripheral vascular disease.
In the short run, diabetes can contribute to a number of acute (shortlived) medical problems:
• infections, as the body’s normal ability to fight infections isimpaired;
• hypoglycaemia (low blood sugar);
• two very serious conditions with very high blood sugar levels (diabetic ketoacidosis and hyperosmolar hyperglycaemic non-ketotic syndrome).
Self-monitoring of blood glucose is a very helpful tool, both for patient and healthcare professional. It helps to adjust therapy and assess the responses to therapy. Patients can themselves immediately assess the impact of an action on their blood glucose level and take prompt action to counteract it.
In addition, it is important to know during which times of the day blood glucose levels are high and what times they are low. Hence, treatment can be tailored to the individual patient’s needs.
Self-monitoring also encourages patients to adhere to their treatment by showing them the actual responses they are having to their treatment.
In fact, studies have confirmed that treatment strategies, where self-monitoring is coupled with adequate diet and exercise, result in improved glycaemic control in both type 1 and type 2 diabetes.
Dr Galea is a medical doctor specialising in family medicine.