JRSM >
Volume 95, Number 9 >
Pp. 453-455
Diabetes Centre, Sheffield Teaching Hospitals Trust, Royal Hallamshire Hospital, Sheffield, UK
Correspondence to: Dr T J Hendra, Department of Geriatric Medicine, Q Floor, Royal Hallamshire Hospital, Sheffield S10 2JF, UK E-mail:Tim.Hendra{at}sth.nhs.uk
 | INTRODUCTION |
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 TOP INTRODUCTION STARTING INSULINORGANIZATION OF CAREREFERENCES |
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In hospital patients with type 2 diabetes, insulin may be part of the initial management of myocardial infarction1, acute illness, hyperosmolar coma and major surgery2. Insulin may also be indicated in the acute management of stroke3. In outpatients the usual reason for insulin therapy is poor glycaemic control manifested by hyperglycaemic symptoms and/or weight loss. Non-specific ill-health or malaise associated with chronic hyperglycaemia is another indication4.
Why does the approach to elderly patients differ from that in younger type 2 patients? Important considerations include:
| STARTING INSULIN |
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TOPINTRODUCTIONSTARTING INSULINORGANIZATION OF CAREREFERENCES |
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Patient assessment
The benefits and disadvantages of insulin therapy must be explained to and
understood by patients and carers; and, as with all elderly patients, a
structured management plan is desirable, based on comprehensive
assessment5.
Performance in activities of daily living can be assessed by the Barthel
index6 and cognitive
status by the abbreviated mental test score
(AMT)7. If the AMT
score is less than 8 out of 10, cognition should be assessed in more detail
with the Folstein Mini-Mental State
examination8; in
addition, mood should be assessed with either the Hospital Anxiety and
Depression Scale9 or
the Geriatric Depression
scale10. This group
of instruments has proved valid for judging patients' ability to inject
insulin independently and to recognize and deal with
hypoglycaemia11.
Cardiovascular risk factors should also be evaluated since control of blood
pressure, stopping smoking and lowering total cholesterol may be of greater
benefit than improving glycaemic control for avoidance of macrovascular
disease12.
Reasons for starting insulin, treatment goals and metabolic
targets
Insulin is usually started when full doses of oral hypoglycaemic agents are
not achieving acceptable glycaemic control or wellbeing; frequently there has
been substantial weight loss. This clinical picture is often referred to as
‘sulphonylurea failure’ though it reflects disease progression and
insulin deficiency.
The results of the UK Prospective Diabetes Study13 indicated that, for elderly type 2 diabetic patients with a good quality of life and able to recognize and deal with hypoglycaemic symptoms, the target glycated haemoglobin (HBA1C) should be <7%. However, this may be inappropriate for frail, socially isolated patients without microvascular complications or with limited life expectancy, for whom the emphasis should be more on avoidance of osmotic symptoms and infections and on modification of cardiovascular risk factors. Many elderly patients with poor glycaemic control and weight loss will benefit from insulin even if they do not achieve this HBA1C target, since insulin therapy is usually associated with weight gain of 4-5 kg. As with younger adults, the goals of patients may differ from those of the healthcare professionals. All agree that symptomatic control is an important indication for insulin, but only a minority of patients take a close interest in glycaemic control and target glucose concentrations14.
| Box 1 Insulin regimens for type 2 diabetes Once-daily isophane insulin Twice-daily isophane insulin Twice-daily premixed short/intermediate acting insulins Basal/bolus isophane and pre-meal short-acting insulins Combinations of bedtime isophane and oral agents
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Choice of insulin regimen
Box 1 outlines the various insulin regimens. Once-daily isophane insulin is
only of use where there is residual pancreatic beta-cell insulin secretion.
Glycaemic control is suboptimal and this regimen is justified only in those
few frail or severely cognitively impaired residents of care homes for whom
the sole aim is relief of hyperglycaemic symptoms. Twice-daily isophane
insulin produces better but not good glycaemic control; post-prandial glucose
peaks still occur and if the dose is increased patients may become
hypoglycaemic before their next meal. For this reason most elderly type 2
patients start with two injections of premixed short and intermediate-acting
insulins in a 30/70
combination15.
Basal/bolus isophane and pre-meal short-acting insulins produce better glycaemic control than other regimens but are expensive and carry a greater risk of hypoglycaemia16. Results in elderly type 2 patients can be as good as in younger adults. Our group has observed that twice-daily isophane insulin can lead to weight gain without improving glycaemic control or wellbeing whereas the basal/bolus regimen substantially reduced glycated haemoglobin and improved wellbeing at 3 months17.
For elderly type 2 patients who have poor glycaemic control but normal or increasing weight, addition of a bedtime injection of isophane insulin to existing oral hypoglycaemic therapy can lessen hyperglycaemia without excessive weight gain. This combination of oral agents with insulin is of particular value for patients with poor diabetic control who do not wish to switch to two insulin injections straight away. The new long-acting insulin analogue, insulin glargine, soon to be marketed in the UK, may prove a useful alternative18.
Mode of insulin delivery
Elderly patients commonly have difficulty in accurately drawing up, mixing
and injecting
insulin19;
therefore premixed combinations of short and intermediate are
preferred20.
Patients with poor eyesight or impaired manual dexterity need advice from a
diabetes specialist nurse on the selection of a pen device. Short, fine,
needles have the advantage of being less painful and are also suitable for
thin skin. Unpredictable insulin absorption may be troublesome; and, for
elderly patients with little subcutaneous adipose tissue, particular care is
needed in pinching up the skin. Differences in subcutaneous tissue may be the
reason why abdominal injections of subcutaneous insulin yield 29% lower
postprandial blood glucose concentrations than injections into the
thigh21.
Most elderly patients starting insulin can inject themselves. A pen device is commonly chosen22, and usual practice is to start with 8 U of premixed short-acting/isophane insulin in a 30/70 mixture twice daily, with the dose increased slowly to achieve fasting pre-breakfast capillary glucose values of around 7 mmol/L and post-meal peaks < 11 mmol/L. Many patients obtain advice on dosage by telephone; some are able to make their own adjustments without contacting the diabetes specialist nurse.
Education and glycaemic monitoring
Education for starting insulin and monitoring, usually given by a diabetes
specialist nurse2,
entails 5-10 face-to-face contacts either in the patient's home or at the
diabetes clinic; these are in addition to telephone contacts. The essential
steps in starting insulin, whether by syringe or by pen, are outlined in Box
2.
Elderly patients receiving insulin should monitor capillary blood glucose; the effect of ageing on the renal threshold for glucose means that urine testing is of little value for assessing glycaemic control. Capillary glucose should be tested twice daily initially as the insulin dosage is gradually increased, though after stabilization a four-point profile twice a week is appropriate. During intercurrent ill-health or when hypoglycaemia is suspected, monitoring should be stepped up. Patients or carers with limited dexterity, impaired vision, or poor memory can select from a range of monitoring devices with the advice of a diabetes specialist nurse. Contrary to expectation the majority (more than 65%) of elderly people starting insulin in clinic can monitor capillary glucose at home with a meter. For the remainder monitoring is usually undertaken by either informal or formal carers, or as a last resort by the district nurse.
| Box 2 Practical steps in starting insulin Assess the need for insulin Assess function, cognition and mood Assess vascular risk Identify treatment goals and metabolic targets Determine insulin regimen, mode of delivery and method of monitoring Decide review date
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All elderly patients starting insulin must be instructed on the symptoms of hypoglycaemia and what to do about it. There is evidence that the knowledge of elderly patients about hypoglycaemia is poor24,25—possibly a reflection of teaching methods. Structured group teaching sessions could be beneficial.
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TOPINTRODUCTIONSTARTING INSULINORGANIZATION OF CAREREFERENCES |
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| Acknowledgments |
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| REFERENCES |
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TOPINTRODUCTIONSTARTING INSULINORGANIZATION OF CAREREFERENCES |
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