1. Older patients may not have polydipsia and polyuria
Diagnosis in older people is more difficult than in younger patients. Older patients:
- May not have the classic symptoms of polydipsia and polyuria, as thirst sensation is impaired and renal threshold for glycosuria increases with age
- Are frequently asymptomatic or may present with non-specific symptoms of fatigue, pain and mood changes
- Commonly experience incontinence or recurrent falls, so diabetes as a potential diagnosis may be overlooked.
2. Be aware that diabetes reduces life expectancy by a decade
Diabetes affects about 15% of the population, with a prevalence of up to 25% among those living in care homes. Yet 3–15% of the elderly population have undiagnosed diabetes.
Diabetes reduces life expectancy by about 10 years and is an independent risk factor for care home admission for older people. Patients with diabetes are twice as likely to be admitted to hospital as those without.
3. Consider screening over-75s annually
In our view, people aged 75 or over should be considered for annual screening for diabetes – although this is slightly different from NICE’s recommendations. Also consider testing high-risk patients who:
- Have a family history of type 2 diabetes in first- or second-degree relatives
- Are of Asian origin
- Have conditions associated with insulin resistance, such as hypertension, dyslipidemia or obesity.
Average time between onset and diagnosis of diabetes is about seven years – sometimes the first presentation in an older person is a hospital admission with hyperosmolar coma. Yet early detection and intervention can improve quality of life and reduce disability.
4. Diagnostic criteria for older people are the same as in younger patients
Diagnostic criteria for diabetes in the elderly are the same as for the general population. Diabetes is diagnosed if plasma fasting glucose is ≥7mmol/l or two-hours-postprandial glucose is ≥11.1mmol/l. Normal glycaemia is plasma fasting glucose <6.1mmol/l or two-hours-postprandial glucose <7.8mmol/l. There are two categories between normal glycaemia and diabetes:
- Impaired fasting glycaemia – when plasma fasting glucose is ≥6.1mmol/l but <7mmol/l.
- Impaired glucose tolerance – when two-hours-postprandial glucose is ≥7.8mmol/l but <11.1mmol/l.
Both categories are at high risk of diabetes and vascular complications.
5. A normal HbA1c does not exclude diabetes
HbA1c is a marker of glycaemic control in patients with established diabetes. It is also used as a diagnostic test with a cut-off level of 6.5% or more. It is convenient for patients, has low day-to-day variability and is standardised internationally. But, while a high HbA1c is diagnostic of diabetes, a normal HbA1c does not exclude diabetes. Also do fasting blood glucose.
6. Do a full assessment after diagnosis
After diagnosis, do a comprehensive elderly person assessment:
- Full clinical examination and screen for diabetes complications
- Evaluation of nutritional status
- Review of functional abilities and daily activities
- Assessment of mental function and any psychological problems, such as depression
- Assessment of mobility, gait and balance
- Questions about erectile dysfunction
- Assessment of social issues, such as isolation and dependency.
7. Use metformin first line but be aware that there are more likely to be contraindications in older people
If there are contraindications or intolerance to metformin, try a short-acting sulfonylurea such as glipizide or gliclazide. Repaglinide is another alternative if metformin or glipizide cannot be used, especially in patients at risk of hypoglycaemia. DPP-4 inhibitors or pioglitazone are alternatives, as monotherapy or add-on therapy. If drug therapy fails, incretin mimetics are suitable, especially for overweight patients, as may be the newer insulin analogues which have fewer hypoglycaemic complications.
8. Have a low threshold when suspecting hypoglycaemia
Hypoglycaemia in the elderly is not necessarily a result of tight glycaemic control but can be because of multiple comorbidities, multi-organ dysfunction and polypharmacy. Risk factors include recent hospitalisation, malnutrition and insulin or sulfonylurea use.
9. Hypoglycaemia occurs at higher blood glucose levels in older people
Hypoglycaemia may occur at a higher blood glucose level and tends to present with non-specific symptoms, so it can be misdiagnosed, for example as stroke.
10. Adjust HbA1c targets depending on health and life expectancy
Targets for HbA1c for fit elderly patients who have life expectancy of around 10 years should be similar to younger patients (≤7%). The goal should be higher (≤8%) for more frail elderly patients with multiple comorbidities and life expectancy of less than 10 years. It is important that targets for HbA1c are individualised, taking account of the patient’s wishes, functional status and quality of life.
Dr Jay Chillala is a consultant in elderly health at the Trafford Division of Central Manchester Foundation Trust, and Dr Ahmed Abdelhafiz is a consultant geriatrician and honorary senior clinical lecturer at Rotherham General Hospital
Dr Chillala is secretary, and Dr Abdelhafiz is chair, to the Diabetes Special Interest Group of the British Geriatrics Society, and both are involved with the Institute of Diabetes for Older People
The British Geriatrics Society (BGS) is a membership association for healthcare professionals with a special interest in the medical care of older people and in promoting better health in old age. It runs two large multidisciplinary conferences each year, alongside several smaller meetings around more focused topics. See bgsevents.org To keep up to date with BGS news follow @gerisoc on Twitter