DIABETES MELLITUS IN THE ELDERLY

K. Anupama, M.D. (Geriatric Medicine), FCD
Consultant Diabetologist
M.V.Hospital for Diabetes and Prof.M.V.DRC, Royapuram

Prevalence

Diabetes mellitus in older adults is under-diagnosed and under-treated. The most important demographic change to diabetes prevalence across the world appears to be the increase in the proportion of people >65 years of age (ADA). By 2030, it is estimated that the number of people with diabetes >64 years of age will be >82 million in developing countries and >48 million in developed countries (ADA). The prevalence of Diabetes mellitus increases with age, and the number of older people with diabetes is expected to grow as the elderly population increases.

The National Health and Nutrition Examination Survey (NHANES III) demonstrated that, in the population over 65 years old, 18% to 20% have diabetes, with 40% having either diabetes or its precursor form of impaired glucose tolerance.













Approximately 95% of older diabetic adults have Type 2 diabetes.
Type 1 diabetes and other causes of secondary diabetes are rare at this age.
There is no age- related adjustment in the diagnostic criteria recommended by the ADA. Glucose level cut-off points that predict complications apply to all ages.


The Human pancreas

The hormone insulin, which is produced by the pancreas, plays a vital role in diabetes.

Diabetes and the Physiology of Ageing

Many physiological changes associated with diabetes mellitus simulate or accelerate ageing processes. This is more frequent when there is a decrease in physiological reserves in many organ systems. Diabetic end- organ damage along with ‘homeostenosis’ can increase the vulnerability of older patients. Multiple factors such as age-related decline in insulin secretion and insulin resistance, adiposity, genetics, decreased physical activity, polypharmacy, and other co-existing illnesses predispose the elderly to diabetes.

Clinical Symptoms

Classic clinical symptoms of diabetes such as polyuria, polydipsia, and polyphagia might not occur in the elderly. The presence of hypoglycemia shows in the form of increasing incontinence, urinary tract infection, lethargy or confusion. Osmotic diuresis may result in volume depletion, orthostatic hypotension and in falls. It can also cause a deficiency of potassium, zinc, chromium, magnesium and other trace nutrients which affects cardiac and other muscle functions. It is also associated with reduced cognitive function and this decline correlates with glucose control.


Complications

Acute complications can be categorized as metabolic and infectious. Non-ketotic hyperosmolar coma occurs predominantly in elderly patients with Type 2 diabetes mellitus. The coma or the alterations in mental status may take several days to clear, lagging behind the correction of serum osmolality. Mortality rates are high. There is an increased risk of severe and unusual infections, particularly malignant external otitis, rhinocerebral mucormycosis, necrotizing fasciitis, emphysematous cholecystitis, and emphysematous pyelonephritis.

Relative risk of chronic complications:

Complication - Relative risk
CAD - (2)
Stroke - (2)
Blindness - (1.4)
Amputation - (10)
Renal disease - (2)

(Relative risk is calculated by comparing with people of the same age who do not have diabetes.)

Management principles

A diagnosis of diabetes is, on an average, associated with a 10-year reduction in life expectancy; but this figure decreases somewhat in advanced old age, where the risks of competing causes of mortality rise exponentially.

Apart from following ADA recommendations for glycemic control during treatment, it is also important to set realistic goals. The patient’s estimated life expectancy, preferences, and commitments; the availability of social support and services, economic issues, and the occurrence of co-existing health problems such as a major psychiatric disorder, a major cognitive disorder, diabetic complications, functional status, and complexity of medical regimen are some of the factors to be considered when setting the goals for treatment.


Diabetic management includes dietary intervention, exercise and medication. In elderly diabetics, malnutrition is more common than obesity. This is more so among patients in long-term healthcare facilities. The level of functional disability is correlated to meal preparation skills. There may be a lack of formal or informal support for obtaining food. Limited financial resources, age-related changes such as a decline in taste and smell perception, poor dentition or xerostomia may result in decreased food intake. Impaired cognitive function increases the patient’s dependence on the care giver.

Exercise is beneficial, although many patients have a limited capability because of co-morbidities and a lack of motivation.


For optimal pharmacological therapy, the target level of glycemic management has to be reassessed according to the patient’s ability for compliance and self-management; risk of hypoglycemia, efficacy of the chosen agent and potential adverse effects. Those who cannot take drugs orally, or fail to achieve the targeted glycemic control, have to take insulin.


Multiple risk factors for hypoglycemia such as renal insufficiency, hepatic dysfunction, cognitive impairment, autonomic neuropathy, and adrenergic blocking drugs, poor nutrition, alcohol, sedating agents, polypharmacy, tight glycemic control and recent hospitalization may co-exist.

Diabetes mellitus results in a ~two-fold risk of death in the elderly. Approximately 50% die of cardio-vascular disease.