Diabetes In Old Age

Stut RW Management Diabetes of in oldAge l

THE MANAGEMENT Professor

OF DIABETES

IN OLD AGE

Robert W. Stout, MD FRCP

Department of Geriatric Medicine The Queen' S University of Belfast Whitla Medical Building 97 Lisburn Rood, Beflast BT9 7BL Northern Irland

Summary

Diabetes becomesincreasingly common with advancing age and this particularly applies to non insulin dependent disabetes. The mechanism for this appears to he insulin resistance ata postreceptor level but there are also deficits in insulin secretion and the sensitivity of the liver to insulin. Elderly patients with diabetes often present with non specific symptoms and may only present when they develop complications. It is important that a correct diagnosis is made as both false positivefalse and negative diagnosesmay have adverseeffects. Diabetes is diagnosed when when thefasting venous plasma glucose is more than 7.8 mmol/l on two or more occasions. Treatment should aim to keep the patient symptom free and avoid the complications of diabetes. General health advice. modification of cardiovascular riskfactors and dietary treatment are primary methods. If drugs have to he used, short-acting sulphonylureas are preferable and insulin is not often needed. Elderly din diabeticpatients, like other elderly patients, may have problems with the use of drugs in old age. Treatment should be monitored but attention paid to the whole of the patient's lifestyle.

are increasing body weight, decreased physical activity, impaired renal function and the ingestion of drugs which cause hyperglycaemia. most commonly diuretic drugs7. In the management of diabetes in older people. avoidance of these factors is the first approach. Characteristics

of Elderly

Diabetic

Symptoms and Signs Suggestive Older People

Diabetes, particularly non insulin dependent diabetes. becomes increasingly common with advancing age and impaired glucose tolerance is also common in older people1. Diabetes is a serious condition in older people and the mortality and morbidity from conditions such as neurological and visual disease and cardiovascular disease is higher in elderly diabetic subjects than in non diabetic people of the same age2.. This may be related to a high frequency of undiagnosed diabetes in older people3. Severe uncontrolled diabetes in older people also has a high mortality, often because it tends to present for medical attention rather late4. Possible mechanisms for glucose intolerance in elderly people include decreased insulin secretion, peripheral insulin insensitivity, either at the cell membrane insulin receptor or at a postreceptor level, and changes in other hormones. Insulin resistance at the postreceptor level is the major mechanism of glucose intolerance in older peopl5’. There is also inappropriate insulin secretion and decreased hepatic sensitivity to insulin6. Other factors which may adversely influence glucose tolerance in older people

Patients

Old age and diabetes interact to produce some characteristic features. Diabetes is a disease with complications in many organ systems so multiple pathology is common in the diabetic subject. Elderly patients tend to have a decrease in their ability to maintain homeostasis and as a result hypoglycaemia. dehydration and confusion are more common in elderly diabetic pstients. Drug treatment may cause problems - the body’s handling of drugs may be impaired. particularly renal excretion; multiple prescribing may result in drug interactions and side effects. while poor compliance may make the management of drug treatment difficult. Self management is more difficult as the patient, because of impaired dexterity, eyesight or memory, may have difficulty in managing treatment regimes or diet. of Diabetes

in

Diabetes may present in a number of ways. General symptoms, including polydypsia, polyphagia, polyuria and weight loss, may occur in older people although they are more commonly absent. Elderly diabetic patients may have recurrent infections, of which urinary tract infections are the most common. They may also present with some of the complications of diabetes, including neurological problems. such as parathesiae, muscle weakness and pain, isolated nerve palsies or autonomic dysfunction which may present as postural hypotension, diarrhoea or incontinence. A common presentation of diabetes in older people is cardiovascular disease. Microangiopathy causing either retinal disease and visual impairment or renal disease is a less common presentation in older people and skin lesions specific to diabetes are not often present. Many elderly diabetic subjects are obese and they may also have abnormalities in their circulating lipids. There may be a family history of diabetes. Frequently, however, there may be no specific presenting features of diabetes in older people and the disease is diagnosed as a result of routine testing.

I 9 I

Risks

in Misdiagnosing

Diabetes

in Older

People

It is important that the diagnosis of diabetes in old age is made correctly as there are problems if the wrong diagnosis is made.

IF a diagnosis of diabetes is made when it is not present, there may be inappropriate treatment with hypoplycaemic agents with a potential for side effects. Unnecessary restrictions on behaviour. affecting, for example, alcohol intake, food choices, stressful situations, fasting and prolonged exercise may occur. There will be an increased cost of unnecessary medical treatment and insurance may be difficult to obtain or expensive. There may be a false assumption of a family history of diabetes.

Not diagnosing diabetes n-hen it is present may result in inadequate preparation or alteration of therapy at the time of stressful events. such as surgery. infections, trauma or serious illness. There n-ill be a lack of awareness of the importance of reducing body weight if obesity is present and there will be a lack of knowledge among family members of the fact that they may he at increased risk. Diagnosis

of Diabetes

in Old Age

The diagnostic classification of diabetes adopted by the World Health Organisation in recent years is not age specific but is conservative enough to accommodate diabetes in older people’. The glucose tolerance test is unnecessary and the diagnosis is made if the fasting venous plasma glucose is more than 7.8 mmol/1 on two or more occasions. Treatment

of Diabetes

Avoidance of smoking are also of great importance. Treatment of lipid disorders in older diabetic patients is more problematic as none of the trials of lipid lowering to prevent cardiovascular disease have studied people over the age of 65 years (or indeed people with diabetes). Nevertheless. it is reasonable to assume that the beneficial effects of treating hypercholesterolaemia, which have been found in younger non diabetic people. will also occur in older people with diabetes whose hyperlipidaemia is not controlled by treatment of diabetes. Diet is the first method of treating non insulin dependent diabetes and as most of these subjects are overweight, the aim is weight reduction. The calorie content of the diet is. therefore. critical and the exact composition of the diet being much less important. Weight loss will produce a rapid decrease in blood glucose levels. If diet is not sufficient, drugs may have to be used. Of the drugs available. the sulphonylureas are preferable to the biguanides as the latter may cause lactic acidosis, particular&~ in stressful situations such as might occur in elderly diabetic patients. The short-acting sulphonylureas. such as glipazide. are most useful as prolonged hypoglycaemia is less of a problem. However. if the patient is well maintained on another drug regime which had been instituted in the past. there is not necessarily any need to change. It is only rarely that insulin is needed in an elderly diabetic patient and in those circumstances a search should be undertaken for pancreatic causes of the diabetes. As a general rule. if the fasting blood glucose is more than 11 mmol/ l, the patient will require treatment with anti-diabetic drugs at an early stage. If the fasting blood glucose is between 8 and 11 mmol/l, dietary treatment should be instituted with the aim of weight reduction, If this is not effective, then oral agents may be added.

in Old Age

The aims of treatment of diabetes in older people are : 1To keep the patient symptom-free 2. To avoid the sequelae of diabetes Management starts with general care. The patient should be advised about the risks of diabetes and in particular the problems associated with oveweight and with inadequate foot care. The importance ofadherence to treatment regimes and attending for review as arranged is also important. Attention to cardiovascular risk factors is assuming increasing importance in the management of diabetes. There is little evidence that reduction of blood glucose will reduce cardiovascular disease. However, many cardiovascular risk factors are common among diabetic patients. Of particular importance is hypertension and the treatment of hypertension by the use of drugs, which do not themselves increase blood glucose levels, is very important even in very elderly diabetic subjects; suitable drugs would be calcium antagonists and angiotensin converting enzyme inhibitors.

Problems with Drug Treatment of Diabetes in Old Age Drug treatment of diabetes in elderly patients may be associated with a number of problems. These included inappropriate ingestion of drugs, multiple prescribing, poor compliance. drug interactions and unwanted effects. The side effects tend to be more common and of more serious significance in older diabetic subjects and impaired renal excretion is a particular problem for those drugs that are excreted by the kidney. Certain drugs are liable to potentiate hyperglycaemia, including steroids, oestrogens, thiazide diuretics, sympathomimetic agents and nicotinic acid. Other drugs can potentiate hypoglycaemia in patients taking insulin or oral anti-diabetic agents, and these include alcohol. beta blockers, warfarin, salicylates and monoamine oxidase inhibitors.

It is important that treatment is monitored but the patient should not have to make unduly frequent or long journeys to a hospital diabetic clinic. Monitoring can take place

in the community or at a clinic which serves other purposes as well, e.g. a geriatric clay hospital. The patient’s blood glucose should be monitored. as should weight and cardiovascular risk factors and there should be an annual inspection of the optic fundi. It is important that treatment is aimed at controlling blood glucose levels but avoiding complications. particularly hypoglycaemia as in the elderly diabetic patient hypoglycaemia is a particularly serious problem, often causing permanent brain damage as well as falls and faints. References

1. Harris MI. Hadden WC, Knowler WC. Bennett PH. Prevalence of diabetes and impaired glucose tolerance and plasma glucose levels in US population aged 20-74 yr. Diabetes 1987;36:523-534. 2. Neil HAW. Thompson AV. Thorogood M, Fowler GH, Mann JI. Diabetes in the elderly: the Oxford Community Diabetes Study. Diabetic Medicine 1789;6:608-613. 3. Croxson SCM. Burden XC. Bodlington M. Botha JL. The prevalence of diabetes in elderly people. Diabetic Med 1771:8:28-31. 4. Gale EAM, Dornan TL. Tattersall RB. Severely uncontrolled diabetes in the over-fifties. Diabetologia 1781:21:25-28. 5. Fink RI, Kolterman OG. Griffin J. Olefsky JM. Mechanisms of insulin resistance in aging. J Clin Invest 1983:71:1523-1535. 6. Chen M, Bergman RN, Pacini G, Porte DJr. Pathogenesis of age-related glucose intolerance in man: insulin resistance and decreased beta-ceil function. J Clin Endocrinol Metab 1985;60: 13-20. 7. Pollare T, Lithell H, Berne C. A comparison of the effects of hydrochlorothiazide and captopril on glucose and lipid metabolism in patients with hypertension. N Engl J Med 1987:321:868-873. 8. WHO Expert Committee on Diabetes Mellitus. Second Report. Geneva: World Health Organization 1980.

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