There will be older people with diabetes who maintain otherwise good health, e.g. have few co-morbidities and good physical
and cognitive function, for whom lower treatment targets, e.g. ≤ 53–58 mmol/mol, remain appropriate.6 Higher
targets, e.g. 58–64 mmol/mol, should be considered for those with co-morbidities, mild frailty or cognitive impairment,
complex medicines regimens or who at risk of hypoglycaemia.6 For people with very poor health, such as those
who have moderate to severe frailty or cognitive impairment, those in long-term residential care or who have end-stage
chronic disease, treatment should aim to avoid symptomatic hyperglycaemia and HbA1c targets in the region
of 70 mmol/mol are appropriate.6
N.B. HbA1c targets > 70 mmol/mol are associated with an increased risk of symptomatic hyperglycaemia,
i.e. glycosuria, dehydration, hyperglycaemic hyperosmolar syndrome, candidiasis, urinary tract infections and poor wound
healing.6 Glycaemic targets should aim to avoid these outcomes.6
Reviewing the benefits and risks of stringent glycaemic targets in older people with diabetes
The benefits of glycaemic control for preventing microvascular complications
The microvascular complications of diabetes, e.g. retinopathy, nephropathy and neuropathy, develop over many years;
long-term glycaemic control prevents the onset and slows the progression of these complications.6 Over time,
however, the balance of benefits and harms associated with maintaining stringent glycaemic targets can change. For example,
someone with limited life expectancy is unlikely to live long enough to benefit from the prevention of microvascular complications
by treating to a stringent target, however, a hypoglycaemia-related fall could accelerate their functional decline and
loss of independence (see: “Intensive glycaemic control increases the risk of hypoglycaemia”). In addition, there are
some clinical trial data showing that the protection against microvascular complications* for patients who have maintained
stringent targets may continue even after the target is dialled back.6
N.B. There is no evidence that maintaining stringent targets will improve renal outcomes in people with established
diabetic kidney disease.7
* Defined as vitreous haemorrhage, retinal photocoagulation or renal failure in the follow-up of the UKPDS trial.8
Further information on the renal complications of diabetes is available from: “Slowing progression
of renal dysfunction in patients with diabetes”.
Intensive glycaemic control is unlikely to prevent the major macrovascular complications of diabetes
The three major clinical trials* investigating the effects of intensive glycaemic control (achieved HbA1c levels
of 46–53 mmol/mol)† in people with longstanding type 2 diabetes (mean age of 60–66 years; mean duration of diabetes of
eight to 12 years) on the risk of macrovascular complications found no benefit of intensive treatment for reducing all-cause
mortality and CVD-related mortality.6, 9 Furthermore, one of these trials, the ACCORD study, found that the
risk of all-cause and CVD-related mortality was significantly higher in the intensive treatment arm (achieved HbA1c levels
of 46 mmol/mol); the reason for this outcome is not completely clear but may relate to hypoglycaemia triggering CVD events.6,
9, 10 For patients with established CVD or high CVD risk, the benefits of addressing non-glycaemic factors, i.e.
blood pressure control, lipid-lowering with statin treatment, aspirin for secondary prevention, and lifestyle modifications,
are likely to be greater than any potential benefits of glucose-lowering with medicines currently funded in New Zealand
for reducing CVD risk.11
* The ACCORD, ADVANCE and VADT studies; for further information on these trials, see:
www.bpac.org.nz/bpj/2010/august/HbA1c.aspx
† The HbA1c levels in the standard treatment groups ranged from 56 mmol/mol to 68 mmol/mol
Intensive glycaemic control increases the risk of hypoglycaemia
Intensive glycaemic control is associated with a significantly increased risk of hypoglycaemia.9, 12 Age-related
physiological changes make older people susceptible to hypoglycaemia and more vulnerable to the adverse outcomes associated
with hypoglycaemia-related falls, e.g. fractures, head injuries, hospital admissions, need for long-term residential care.13 Hypoglycaemia
also increases the risk of cognitive decline, dementia, myocardial infarction, stroke and death.14, 15 Fear
of hypoglycaemia can cause significant anxiety (e.g. worrying about not waking up in the morning) and lead to or worsen
social isolation and/or depression in older people by affecting their confidence to leave the house to engage in social
activities, exercise or travel.
Hypoglycaemia in older people can manifest as non-specific neurological symptoms, e.g. confusion, dizziness,
weakness, visual disturbances, rather than adrenergic symptoms, e.g. tremors, sweating. Repeated hypoglycaemic episodes
can lead to hypoglycaemia unawareness, which in turn increases the risk of hypoglycaemia-related mortality.14 Clinicians
should have a low threshold of suspicion for hypoglycaemia in older patients if they or their caregivers report any possible
symptoms.16
It is also important to ensure that patients and their family/whānau understand “sick day” management and how to adjust
regimens to accommodate any missed meals or changes in activity to reduce the risk of hypoglycaemia.
Stringent HbA1c targets increase the risk of polypharmacy
HbA1c levels often increase over time and intensification of treatment is needed to achieve an agreed target.
For many patients this means using multiple glucose-lowering medicines. If other co-morbidities are present, the risk
of polypharmacy and associated adverse outcomes, e.g. poor adherence, medicine-medicine interactions, medicine-disease
interactions, is increased. Selecting a less stringent HbA1c target requiring fewer medicines or a simplified
regimen (e.g. switching to a combined metformin + vildagliptin tablet) while still maintaining reasonable glycaemic control
can help to minimise the adverse outcomes associated with polypharmacy.
