DIABETES IN ELDERLY
By Egongu Max
7th September, 2021
Introduction
Age is one of the most important risk factors in the development of prediabetes and type 2 diabetes [1]. A visible growth in of population of elderly people has been observed around the world for sedveral decades, and it is estimated that this trend will continue.
Pathophysiology
The process of aging of the human body leads to impairment of energy homeostasis and abnormalities in carbohydrate metabolism.
The most important causes of hyperglycaemia are thought to be deficiency of insulin secretion developing with age and growing insulin resistance.
The Baltimore Longitudinal Study of Aging demonstrated that insulin secretion after glucose load decreases with age even after taking into account the influence of obesity and distribution of adipose tissue. Tests on the kinetics of insulin excretion in elderly people revealed that in comparison with younger people postprandial excretion of insulin is irregular and the amplitude of consecutive insulin pulses is lower
Impairment of function of β cells and dysfunction of insulin secretion in people suffering from type 2 diabetes are even deeper, and they are connected with almost total loss of the first phase of insulin secretion.
Moreover, the sensitivity of pancreatic β cells for incretins decreases in the elderly.
The effectiveness of incretins is smaller and it results in lower postprandial insulin levels and weaker suppression of glucagon secretion.
The next important factor leading to increased glucose level in blood is insulin resistance, which grows with age.
Distribution of adipose tissue in the elderly is changing (increased amount of visceral adipose tissue), and the amount of fat tissue grows in contrast to muscle mass, which decreases with age.
The result of the process of aging is dysregulation of the hypothalamic-pituitary-adrenal axis (HPA axis), which leads to a relative prevalence of cortisol.
Cortisol, as a catabolic hormone, is responsible for proteolysis, and its higher level leads to reduced muscle mass.
Additionally, cortisol leads to hepatic insulin resistance.
With age, muscles lose strength and mass (this phenomenon is called sarcopaenia).
Insulin-dependent glucose uptake by skeletal muscles is reduced due to suppression of insulin receptors and glucose transporter GLUT-4.
It has been demonstrated that in the seventh decade of life the mass of muscle tissue is reduced by 30-40% in favour of adipose tissue. Reduced physical activity of elderly people escalates this process. Co-existing obesity, increased adrenergic tension connected with age, decline in kidney functioning, and use of potentially diabetogenic drugs (diuretics, beta-adrenolytics, corticosteroids, psychotropic drugs, amiodarone) are additional factors promoting impairment of glucose metabolism and diabetes in the elderly.
Treatment
Metformin; First choice of treatment of it's efficiency in decreasing HbA1c level, beneficial effect on body mass and lipid profile
Sulphonylureas
These drugs are effective in decreasing glycaemia, are characterised by relatively good tolerance and are often attached to metformin.
Gliptins
Gliptins – dipeptidyl peptidase-4 inhibitors (iDPP-4) – are a new group of medications successfully used in elderly people. DPP-4 inhibitors raise endogenous incretin levels (mainly glucagon-like peptide-1 – GLP-1), which increases insulin secretion and inhibits glucagon release.
Glucagon-like type peptide-1 analogue
Gliptins – dipeptidyl peptidase-4 inhibitors (iDPP-4) – are a new group of medications successfully used in elderly people. DPP-4 inhibitors raise endogenous incretin levels (mainly glucagon-like peptide-1 – GLP-1), which increases insulin secretion and inhibits glucagon release.
Thiazolidinediones.
This drug influences transcription of numerous genes, leading to improvement of peripheral tissue sensitivity for insulin, mainly adipose tissue.
Flozins.
Flozins inhibit re-uptake of glucose in renal proximal tubule, resulting in an increase in glucose excretion in urine. It leads to decreased glucose level in the blood and loss of calories.
Insulin.
Insulin is still a necessity in the case of some elderly people when orally administered drugs have to be discontinued due to lack of efficacy or contraindications (e.g. because of renal insufficiency).
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