This article considers the practice nurse's approach to supporting older people to manage their diabetes. It is essential to individualise care and to interpret the older person's diabetes in the context of their overall health concerns, including reference to co-morbidities, cognitive function, lifestyle, social setting, and life expectancy (International Diabetes Federation, 2017; Hambling et al, 2019). The important subject of end-of-life care lies outside the scope of this article.
Maintaining safety and focusing on a person's quality of life and autonomy are important principles. Pharmacological treatment goals must be realistic, acknowledging the metabolic consequences of old age, the risks of hypoglycaemia and the dangers of polypharmacy. A holistic appraisal is crucial and primary care is well positioned to do this; practice nurses involved in diabetes care have an important role working alongside these patients.
What is special about the older person with diabetes?
There are increasing numbers of people with diabetes over the age of 65 years. This is principally driven by the rise in prevalence of type 2 diabetes (T2DM) that correlates with greater rates of obesity (increasing insulin resistance and declining pancreatic insulin secretion as a result of declining beta-cell function).
Many older people will have had diabetes for many years (very likely in the case of type 1 diabetes [T1DM]) during which both macrovascular (ischaemic heart disease, cerebrovascular disease, peripheral vascular disease) and microvascular (neuropathy, nephropathy, retinopathy) complications may have developed. Even asymptomatic individuals with T2DM can already have established macrovascular and microvascular damage at the point of diagnosis (Palladino et al, 2020).
Diabetes has further adverse impacts on physical and mental health in older people. For example, the risk of falling is increased around three-fold in people with diabetes (Schwarz et al, 2002). There is evidence of an association between diabetes and Alzheimer's disease and cerebrovascular dementia (Cheng et al, 2012), and the relationship between diabetes and depression appears to be bi-directional in causality (Maraldi et al, 2007).
Older people typically have reduced rates of excretion and metabolism that increase the risk of drug toxicity. Renal and hepatic function should be taken into account when choosing medication; lower doses may be necessary and indeed certain drug classes may need to be avoided altogether (Hamblin et al, 2020). Many older people are on complex drug regimens where the likelihood of drug interaction is high (Hamblin et al, 2020). Drug toxicity should always be considered as a cause of illness and confusion in older people.
Avoidance of hypoglycaemia (from anti-diabetic medication, notably sulphonylureas and insulin therapies) is of paramount importance in older people; not only are they at increased risk of experiencing hypoglycaemia but the consequences may be more profound.
Good care can help avoid hospital admission, bearing in mind that approximately one in six people occupying hospital beds has diabetes, with the vast majority being over 65 years old (Gadsby, 2018).
Making a holistic assessment
In addition to reviewing biochemistry, medication and risk of hypoglycaemia, an assessment of co-morbidities, lifestyle, mood, cognitive status and social support are required to achieve a true functional status (rather than relying on age) (International Diabetes Federation, 2017; Hambling et al, 2019). Clearly, solving problems in the older person with diabetes requires a holistic approach.
Areas to be considered at review are summarised in Table 1.
Table 1. Assessment of the older person with diabetes
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Newly diagnosed diabetes in the older person
The most common form of diabetes diagnosed in older people is T2DM. Features supporting this diagnosis include raised body mass index (especially if BMI >30 kg/m2), sedentary lifestyle, family history of T2DM (especially first-degree relatives), and higher risk ethnicity (South Asian, Afro-Caribbean, Chinese). Individuals may well be asymptomatic and so there should be a low threshold for testing for diabetes in those with predisposing factors.
In people with a normal BMI, T2DM remains a possibility but this situation could indicate insulin deficiency rather than insulin resistance (and thus a requirement for insulin) (Ferrannini, 1998). Late-onset T1DM is suggested by weight loss and osmotic symptoms of polyuria and polydipsia or diabetic ketoacidosis (DKA) requiring urgent hospital admission for immediate commencement of insulin.
However, less severe osmotic symptoms and weight loss may herald a slower progression to insulin dependence in the case of LADA (latent autoimmune disease in adults) (Naik and Palmer, 2003). It may be several years before an absolute need for insulin develops and it is not uncommon for the individual to be categorised as having T2DM because of the age of onset and the finding that oral hypoglycaemics are initially effective. The risk of decompensation to DKA remains with the key indicator of insulin deficiency being the finding of ketones in blood (or urine). A personal or family of autoimmune disease strengthens the possibility of autoimmune diabetes.
A further diagnostic possibility could be pancreatogenic diabetes and this should be suspected with a past history of pancreatitis (commonly associated with excess alcohol) (Duggan et al, 2017). There may be symptoms of weight loss, abdominal pain and loose stool (consistent with malabsorption due to pancreatic exocrine deficiency). An abdominal CT scan can clarify the diagnosis. Further tests are usually carried out in secondary care (in this case negative islet cell antibodies). Oral treatments can be tried but, ultimately, insulin is likely to be needed.
Perhaps the important point is to keep an open mind diagnostically as to the type of diabetes an individual might have and to be prepared to change treatments if necessary.
The danger of hypoglycaemia in the older person
The risk of hypoglycaemia arises from over-treatment of hyperglycaemia. The treatments carrying the highest risk of inducing hypoglycaemia are insulins, and the insulin secretagogues – sulphonylureas (eg gliclazide, glimepiride) and the lesser used meglitinides (eg repaglinide, nateglinide).
With increasing age and duration of diabetes the physiological responses to falling glucose levels become blunted (Heller et al, 2011). Therefore, there may be a loss of the autonomic warning symptoms of hypoglycaemia (which are usually triggered at blood glucose levels <4 mmol/L) (see Table 2) as a consequence of a deficient catecholamine (adrenaline) response. Under these circumstances, with the person unaware of the situation, there is a danger of progression to very low blood glucose levels (typically around 2 mmol/L) and the more serious problem of neuroglycopaenia (see Table 2) (Diggle, 2015; Diabetes UK, 2021). The gravity of this situation may be magnified by a sluggish corrective response of glucagon (which stimulates release of glucose from the liver). Cognitive decline exacerbates the problem of hypoglycaemic awareness.
Table 2. Symptomatic response to hypoglycaemia
| Autonomic symptoms | Neuroglycopaenic symptoms |
|---|---|
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Therefore, in older adults the combined effects of a deficient adrenaline response and glucagon inadequacy can result in an absence of warning symptoms with rapid descent to severe hypoglycaemia, by which time cognitive dysfunction has taken hold. Under these circumstances there is a risk of serious injury, including fractures and head injuries, and also of cardiac arrhythmias and cardiovascular events (Khunti et al, 2015). Severe hypoglycaemia is likely to result in hospital admission (Farmer et al, 2012).
Setting an HbA1c target
The benefits accrued from intensive glycaemic control can take years to become apparent (Holman et al, 2008). With increasing duration of diabetes, the benefit of tight glycaemic control lessens, and indeed there is evidence that this may actually increase cardiovascular morbidity and mortality (Inzucchi et al, 2015). There is an association between both low and high levels of glycaemic control and increased mortality in older people with diabetes (Forbes et al, 2018).
In setting an appropriate HbA1c target in older people, key elements are functional status (which is arrived at from the holistic assessment described above), life expectancy and risk of hypoglycaemia. Table 3 summarises this approach (Hambling, 2020).
Table 3. HbA1c targets in the older person
| Functional status | Risk of hypoglycaemia | Glycaemic target |
|---|---|---|
| Healthy, functionally independent, long life expectancy | Diet control or oral medication with low risk of hypoglycaemia | HbA1c 53–59 mmol/mol |
| Complex health or social care needs, intermediate life expectancy, mild-moderate frailty | Oral glucose lowering treatments with low risk of hypoglycaemia | HbA1c 53–64 mmol/mol |
| Fit, healthy | SU or insulin therapy | HbA1c 53–64 mmol/mol |
| Very complex needs, poor health, frail | Any treatment | HbA1c 59–69 mmol/mol |
| Complex, intermediate health or social care needs, mild frailty | Insulin treatment | HbA1c 59–69 mmol/mol |
| End-of-life palliative care | Any treatment | Avoid symptomatic hyper-or hypoglycaemia |
Choosing treatments for hyperglycaemia
After addressing lifestyle issues, metformin remains the first-line treatment for T2DM in older people, effectively lowering HbA1C, carrying a low risk of hypoglycaemia, avoiding weight gain and offering cardiovascular benefit (Holman et al, 2008). It should be used with caution in renal failure (risk of lactic acidosis), with consideration of dose reduction when GFR <45 ml/min and withdrawal should GFR fall to 30 ml/min (Inzucchi et al, 2014). If gastroenterological side-effects prove troublesome, it is worth trying the slow-release preparation which may be better tolerated (National Institute for Health and Care Excellence [NICE], 2015a).
Sulphonylureas (and meglitinides, eg repaglinide) should be used cautiously in older people because of the associated risk of hypoglycaemia, and if they are to be used then institution of glucose monitoring should be considered, especially in those who drive (NICE, 2015a). Pioglitazone is not prone to causing hypoglycaemia and can be used in renal failure, but there is always the worry of inducing heart failure (Dormandy et al, 2005), and further concerns would be the association with fracture and bladder cancer, therefore it may not be an optimum treatment of choice in older people with type 2 diabetes. Both sulphonylureas and pioglitazone lead to weight gain (Davies, 2018).
DPP-4 inhibitors (gliptins) are a safe treatment option for older people. They are well tolerated, weight neutral, carry a low risk of hypoglycaemia and can be used down to end-stage renal failure. Linagliptin is minimally renally excreted and so can be used without dose change in renal failure. Cardiovascular safety has been demonstrated (Scottish Intercollegiate Guidelines Network [SIGN], 2017; Davies et al, 2018).
Glucagon-like peptide 1 receptor agonists (GLP-1RAs) may, in the right context, be useful agents in the older person, particularly where obesity is present. Once-weekly injectable preparations could be advantageous, especially if there is a requirement for another person to administer treatment. The first oral formulation of a GLP-1 RA is now licensed for use (Pearson et al, 2019), which may also be useful in this group. The GLP-1 RAs offer large improvements in glycaemic control (with low risk of hypoglycaemia) together with weight loss, can provide cardiovascular and renoprotection and can be used safely in chronic kidney disease down to low eGFR values. The most troublesome side-effects are gastrointestinal (SIGN, 2017; Davies et al, 2018; Buse et al, 2020).
Sodium-glucose co-transporter-2 (SGLT-2) inhibitors can also achieve impressive reductions in HbA1c with a low risk of hypoglycaemia. Additional benefits include weight loss, a small lowering of blood pressure, secondary prevention of cardiovascular disease, protection against heart failure and impressive improvements in renal outcomes (SIGN, 2017; Davies et al, 2018, Buse et al, 2020). Problems with use include an increased risk of genital thrush (and to a lesser extent urinary tract infection), more frequent micturition, a risk of inducing postural hypotension and a small increased risk of diabetic ketoacidosis (Fralick et al, 2017).
Where possible in T2DM, insulin is better avoided in older people because of the risk of hypoglycaemia and the complexity of administration, and under many circumstances a GLP-1 RA would be recommended as the first choice injectable treatment (Buse et al, 2020). If insulin therapy is essential (T1DM, LADA, pancreatogenic diabetes) then a full education package including advice on avoidance, recognition, and treatment of hypoglycaemia along with blood glucose monitoring and interpretation will be essential (NICE, 2015a; NICE, 2015b). Most commonly in T2DM the starting point will be a basal insulin. Insulin administration can be intensified to twice daily mixed biphasic injections or a basal-bolus regime; older patients with T1DM are likely to have been on such treatments for many years.
The dangers of polypharmacy and over-treatment
Polypharmacy is potentially a major problem in the older person with diabetes. De-intensification and simplification of medication regimes should always be born in mind. Adherence to a complex medication regime may be an unrealistic goal for the patient, especially in the face of cognitive impairment. Assistance in correctly taking medication from a partner, family or friends may be required.
It may be appropriate to consult the pharmacist to discuss if the medication can be presented in a more user-friendly form. Combination treatments and long-acting drug formulations may ease the tablet burden and soluble/dispersible or liquid formulations can be valuable in those with swallowing difficulty. Insulin regimes may be chosen primarily with safety and ease of administration in mind, eg in T2DM a long-acting basal insulin analogue may minimise the risk of hypoglycaemia, and if a third party has to administer the injection it will only require one visit per day; in T1DM it may be simpler to choose a twice daily premixed insulin (rather than basal-bolus therapy) to reduce the number of injections and avoid the confusion of using more than one type of insulin.
Medication reviews should be regular, removing any non-essential treatments to simplify the drug regime, noting that polypharmacy increases the risk of drug interactions. In general, it is good practice to try to use the least number of drugs at the lowest effective dosages (Gadsby, 2018).
Case study
Case overview
Mike is 78 years old and was diagnosed with T2DM 19 years ago. Six years ago he experienced a myocardial infarction. He has osteoarthritis of his hip that requires the use of a stick to walk and has had a stair lift installed. Mike is able to wash, dress and cook for himself. In the past Mike has received input from the physiotherapist and occupational therapist. He lives alone and strongly wishes to remain as independent as possible. Mike's daughter lives nearby and helps with shopping, housework and organising his medications. Mike has friends who drop in to see him and he enjoys time in the garden and watching sport on TV. He does not regularly check capillary glucose readings.
Medication list
Metformin 1000 mg bd, gliclazide 80 mg bd, aspirin 75 mg od, omeprazole 20 mg od, atorvastatin 80 mg od, bisoprolol 2.5 mg od, lisinopril 20 mg od, indapamide 2.5 mg od, doxazosin 4 mg bd, sertraline 50 mg od, co-codamol 8/500 prn, amitriptyline 25 mg nocte.
Review
Mike is reviewed because he has been experiencing episodes of shakiness, palpitations and sweating (notably after a long time spent gardening) and dizziness that appears to be associated with sudden standing. He also reports a generalised muscle ache and stiffness.
Cognition appears intact from a mini-mental test score and screening questions would suggest Mike is not significantly depressed. BP 117/58 with postural drop on standing. BMI 31.2 kg/m2.
Investigations are arranged that show: HbA1c 51 mmol/mol; eGFR 49 mL/min/1.73m2 (stable); LFTs normal; TSH 3.2 u/L; cholesterol 3.4 mmol/mol, non-HDL cholesterol 2.1 mmol/mol; Hb 132 g/dL.
Case outcome
Although Mike is not recording capillary glucose readings, the tight glycaemic control, as evidenced by his low HbA1c result, and his use of gliclazide do raise the strong possibility that he might be experiencing episodes of hypoglycaemia. The cause of Mike's dizziness may be multifactorial but postural hypotension would certainly seem to be a significant contributor.
As an older person living alone, with co-morbidities and a significant degree of frailty, Mike is vulnerable to hypoglycaemia and its consequences. Tight glycaemic control is inappropriate under these circumstances and an HbA1c up to 64 mmol/mol would be acceptable. Mike's gliclazide was therefore discontinued. If glycaemic control were subsequently to rise above target a safer option than a sulphonylurea would be a DPP-4 inhibitor which should avoid the risk of hypoglycaemia and is compatible with his chronic kidney disease.
Mike's BP is unnecessarily low and as doxazosin would be particularly implicated with his postural hypotension this treatment was stopped. If symptoms of dizziness did not clear and BP remained on the low side then consideration could be given to withdrawing his thiazide diuretic.
The muscle symptoms that Mike reports may relate to his high dose of atorvastatin and could contribute to mobility problems. Accordingly, the dose of atorvastatin was reduced to 20 mg daily.
Finally, as Mike appears neither to be anxious or depressed nor reporting sleep difficulties, his night-time dose of amitriptyline was reduced to 10 mg to reduce anti-cholinergic side-effects with a view to subsequent discontinuation. There may be opportunity to reduce and stop his antidepressant in the future.
Reducing cardiovascular risk
Use of antihypertensives and statins, and smoking cessation, remain crucial (and of more importance than glycaemic control [Solomon, 2003]) in reducing cardiovascular risk in the older person with diabetes. Angiotensin-converting enzyme (ACE)-inhibitors (eg ramipril, lisinopril) and angiotensin receptor blockers (eg losartan, irbesartan) are first-line antihypertensive choices provided they do not induce a substantial deterioration in renal function. Dihydropyridine calcium channel blockers (eg amlodipine) and thiazide-like diuretics (eg indapamide) are further antihypertensive options (NICE, 2015a).
NICE recommend blood pressure targets of 140/90 mmHg in individuals with diabetes (135/85 with ambulatory or home BP monitoring) lowered to 130/80 if they have retinopathy, nephropathy or cerebrovascular disease. Over the age of 80 years targets are 150/90 (145/85 on ambulatory or home BP monitoring) (NICE, 2019). Should postural hypotension be problematic then further relaxation of goals would be appropriate.
Atorvastatin 20 mg daily is recommended by NICE for primary prevention of cardiovascular events and 80 mg daily for secondary prevention in both T1DM and T2DM (NICE, 2014). Should myalgia prove problematic then reduced doses, a switch to an alternative statin or use of ezetimbe can be tried but treatment should not be at the expense of impaired mobility or balance.
The use of aspirin (or clopidogrel) in older people with diabetes is better reserved for those with overt cardiovascular disease (ischaemic heart disease, cerebrovascular disease, peripheral vascular disease), ie for secondary prevention rather than primary prevention, as in the latter situation benefits are small and counterbalanced by the risk of gastrointestinal bleed (Bowman et al, 2018; NICE, 2020a; NICE, 2020b). If antiplatelet medication is used, gastroprotection with a proton pump inhibitor should be considered in older people (especially if over the age of 70 years or with other factors that might predispose to a GI bleed).
Conclusion
It is important that practice nurses use an individualised approach aiming to maximise safety, preserve autonomy and improve quality of life when helping the older person to manage their diabetes. Older people are at greater risk of hypoglycaemia compared to younger people and the consequences of hypoglycaemia can be more profound for this group. HbA1c targets should take account of general health, including mental health and cognitive status, co-morbidities, social care needs, life expectancy and risk of hypoglycaemia. Regular medication reviews are important and where appropriate regimes should be simplified to minimise the risk of drug side-effects and interactions in older people.
Key Points
- A holistic assessment is essential in managing diabetes in older people. An individualised approach aiming to maximise safety, preserve autonomy and improve quality of life is needed
- Compared to a younger population, older people are at greater risk of hypoglycaemia and the consequences of hypoglycaemia can be more profound
- HbA1c target should take account of general health, including mental health and cognitive status, co-morbidities, social care needs, life expectancy and risk of hypoglycaemia
- In choosing treatments for glycaemic control, important considerations include avoiding treatments that carry a high risk of hypoglycaemia where possible, and selecting medication that is compatible with renal and hepatic function
- Polypharmacy is a major concern in older adults. Regular medication reviews are important and where appropriate regimes should be simplified to minimise the risk of drug side-effects and interactions
- Cardiovascular risk factors should be addressed in line with NICE recommendations
CPD reflective practice:
- Why are older adults at higher risk of experiencing hypoglycaemia compared with younger populations?
- Why can hypoglycaemia be more dangerous in older people?
- How could you reduce the risk of polypharmacy in your older patients?