Maternal malnutrition and overnutrition during pregnancy are associated with subsequent type 2 diabetes in the offspring.⁵ Primary prevention needs to start with pre-conception counselling of women planning pregnancy, with advice on exercise and nutrition to maintain optimal weight and nutritional status during the pregnancy.

Infant supplements

A systematic review of observational studies found that giving infants vitamin D supplements could protect them from type 1 diabetes.⁶ Infants given the supplement had an almost 30% reduced risk of diabetes compared with those who were not supplemented. This is particularly important in breastfed infants of vitamin-D-deficient mothers.

Weight management

Preventing or reversing metabolic syndrome involves weight loss and waist circumference reduction through diet and increased activity, and maintaining goal levels of blood pressure, lipids and lipoproteins and blood glucose. BMI per se is now seen as a less accurate marker of cardiovascular risk. It is not just the presence of excess weight but the pattern of weight distribution that is important. Abdominal or ‘apple’ obesity is the pattern associated with greater risk. The so-called ‘pear’ distribution of fat, mostly around the hips and legs, is less of a problem than the apple distribution. The measurement to determine which category a patient falls into is the waist–hip ratio. If this is above 1.0 for women or 0.9 for men, the person is said to have the apple distribution of fat; below these figures the person would be classified as having the pear distribution.

The mainstays of primary prevention of diabetes are:

• a healthy diet from conception onwards, including a wide range of regular physical activity

• avoidance of sedentary activities

• maintenance of a healthy weight

• moderate alcohol consumption

• avoidance of smoking

• avoidance of environmental toxins.

Case detection

Proactive screening of asymptomatic patients

There is an asymptomatic phase of undetected diabetes mellitus that provides an opportunity for early detection, reducing the incidence of long-term complications. Microvascular complications such as retinopathy, neuropathy and renal disease are commonly already present at the time of diagnosis of type 2 diabetes.

The following groups of asymptomatic patients should be tested:⁷

• individuals over 55 years of age

• people aged 45 or older who have one or both of the following risk factors:

• obesity with BMI > 30

• hypertension

• Aboriginals and Torres Strait Islanders aged 35 or older

• certain high-risk non-English-speaking background groups aged 35 or older (specifically Pacific Island people, people from the Indian subcontinent or of Chinese origin)

• all people with impaired glucose tolerance or impaired fasting glucose

• all people with clinical cardiovascular disease (myocardial infarction, stroke, angina)

• women with polycystic ovary syndrome who are obese

• patients taking antipsychotic drugs

• women with a past history of gestational diabetes.

FIGURE 26.2 Pear body

FIGURE 26.3 Apple body

Blood glucose level

The test of choice for diagnosis is fasting plasma glucose performed in an accredited laboratory. Random measures may be used.

Interpretation of blood glucose level (BGL) results:

• < 5.5 mmol/L—diabetes unlikely

• ≥ 7.0 mmol/L or more fasting or ≥ 11.1 mmol/L random—diabetes likely

• 5.5–6.9 mmol/L fasting, or 5.5–11.0 mmol/L random—perform a glucose tolerance test (GTT).

Re-testing should be performed under the following circumstances:

• on a different day, to confirm a BGL test suggesting a diagnosis of diabetes

• 1 year later for people who have an initial test suggesting diabetes that is not confirmed on the subsequent test

• each year for people with impaired GTT or impaired fasting glucose

• every 3 years for people in high-risk groups with negative screening tests.

People in high-risk groups with negative screening blood glucose tests are also at high risk for cardiovascular disease and should be encouraged to reduce their cardiovascular risk factors.

Glucose tolerance test

People found to have impaired glucose tolerance, where glucose levels are above normal but fall short of a diagnosis of diabetes, are at higher risk of later developing type 2 diabetes and also at higher risk of cardiovascular disease. Approximately one-third of people with impaired glucose tolerance will develop type 2 diabetes.

MANAGEMENT

INITIAL ASSESSMENT

History

Initial assessment of the patient with diabetes involves a comprehensive medical, social and lifestyle history:

• food diary for 3–7 days to assess current eating patterns

• exercise diary—including current patterns of exercise frequency, duration and intensity

• psychosocial assessment (stress, anxiety, depression)

• current medication and supplements

• tobacco and alcohol consumption

• family history of diabetes, cardiovascular disease, osteoporosis, coeliac disease and hyperlipidaemia

• review results of recent investigations where available.

Examination

Comprehensive physical examination, including:

• blood pressure, cardiovascular assessment

• peripheral neurological assessment

• height, weight, BMI

• waist circumference

• feet—ulcers, neuropathy, peripheral vascular disease

• urinalysis (especially looking for asymptomatic urinary tract infection and microalbuminuria)

• visual acuity, retinal fundoscopy

• ECG.

Laboratory tests and further investigations:

• fasting BGL

• HbA_1c every 6 months

• urinary albumin/protein

• full blood examination including haemoglobin and white cell count

• C-reactive protein

• homocysteine (cardiovascular risk)

• thyroid function tests (TFT) (TSH and free T₄)

• fasting lipids (cholesterol and HDL)

• micronutrient assessment (especially iron, folate, vitamin B₁₂, B₆)

• coeliac serology (association between type 1 diabetes and coeliac disease—1 in 20 people with type 1 diabetes have coeliac disease and as many as 1 in 10 test positive for transglutaminase IgA autoantibodies)

• baseline retinal and visual assessment

• bone densitometry for patients aged over 40.

Type 1 or type 2?

Blood tests can help distinguish between type 1 and type 2 diabetes.

• Tests for islet cell and anti-GAD antibodies are positive in 90% of patients with type 1 diabetes.

• C-peptide levels would be abnomally low in type 1 and normal in type 2 diabetes.

INITIAL MANAGEMENT

The aim of initial management is to establish glycaemic control, normalise lipid and lipoprotein levels and motivate the patient to make significant and lasting changes to their lifestyle, including exercise and weight control.

A significant feature of the initial management phase includes patient education in self-monitoring, symptom awareness (including signs of hypoglycaemia), diet and exercise, and self-care.

A decision needs to be made about appropriate medication and supplements (see below).

Education

As is the case with the successful management of any chronic disease, the healthcare professional acts as informed advisor to the patient. It is the person living with diabetes who has to ‘walk the walk’, deciding on their level of compliance with recommended treatments. This involves ‘big picture’ decisions like starting oral hypoglycaemic agents or insulin treatment, or wholesale lifestyle adjustment, as much as the micromanagement of individual risk factors, such as choice of exercise program and the finer details of dietary components. For this reason, management plans must have mutually agreed, achievable goals.

The primary aim of treatment of diabetes is to optimise blood sugar control in order to increase longevity and quality of life, and to minimise complications of the disease. When devising a management plan, you will need to consider the patient’s level of education, cultural beliefs, preferences and financial resources. For example, although a personal trainer might be a desirable way to motivate a person to exercise regularly, this would not be affordable for many. A walking group might be an option.

Education also needs to include significant others in the patient’s life. Whoever has responsibility for food shopping and preparation in the household will need to be involved in education about dietary changes. Exercise programs will need to involve the encouragement of significant others, to aid compliance.

Home blood glucose monitoring is an essential part of the management of diabetes, initially under close supervision. In the early stages after diabetes is diagnosed, BGL readings three or four times a day are recommended. Once blood glucose levels stabilise, monitoring can be reduced to once or twice a day, one or two days a week.

Symptoms of hypoglycaemia

Patients diagnosed with diabetes will need to be aware of the early signs of hypoglycaemia so they can take steps to correct their BGL. Symptoms occur when the BGL falls too low (below about 4.0 mmol/L). They include:

• shaking

• hunger

• rapid heartbeat /palpitations

• tingling around the mouth and lips

• lethargy

• headache

• dizziness.

If not corrected, this can proceed to confusion, slurred speech, unsteady gait and drowsiness leading to unconsciousness.

If a patient is hypoglycaemic but conscious and able to drink, a sweet drink such as fruit juice is simplest and will help to correct the problem within minutes.

If the patient is unconscious, administration of glucagon 1 mg SC, IV or IM will be necessary. People with diabetes, and their families and associates, should be instructed in the use of a ‘hypo kit’.

If this fails to restore consciousness, follow glucagon with IV 50% glucose 20–30 mL.

ONGOING MANAGEMENT

Successful long-term management of diabetes requires a commitment by the patient to lifelong healthy lifestyle measures. Management programs need to be negotiated with the patient so that realistic goals can be set which take into account the patient’s current state of health and fitness, their individual food and activity preferences, their financial status and their access to healthcare professionals and facilities.

The general practitioner is most often where the initial diagnosis and investigation occurs and plays a central role in coordinating care involving other healthcare professionals. This coordinating role requires excellent communication between all professionals involved in care. It also depends upon a reliable and efficient recall and reminder system.

Once the initial diagnosis and management are in place, the patient needs to be linked up with other healthcare professionals, ideally including:

• endocrinologist

• diabetes education clinic

• dietician

• podiatrist

• optometrist/ophthalmologist

• community pharmacist

• fitness professional

• appropriate complementary practitioner(s).

Goals of management

People with diabetes and prediabetes should be encouraged to achieve and maintain the following targets:

• fasting BGL 4.0–6.0 mmol/L

• HbA_1c 7.0–7.9% (over-zealous management below these levels increases the risk of severe hypoglycaemia and may be associated with increased mortality)

• total cholesterol < 4.0 mmol/L

• HDL cholesterol > 1.0 mmol/L

• LDL cholesterol < 2.5 mmol/L

• triglycerides < 1.5 mmol/L

• blood pressure ≤ 130/80 mmHg

• BMI ≤ 25 kg/m² where appropriate

• urinary albumin excretion < 20 mg/L (spot collection)

• cigarette consumption zero

• alcohol consumption 2 standard drinks/day or less

• exercise 30–45 minutes/day minimum, total > 150 minutes/week.

The ACCORD study reported by the NIH in 2008 suggests that aiming for stricter control for type 2 diabetics in the range of a HbA_1c of ≤ 6.5 was associated with higher mortality than those controlled in the range of 7.0–7.9.⁸

Immunisation

Consider influenza vaccination annually and pneumococcal vaccination every 5 years.

Diet

Careful and well-informed dietary management is central to the management of all types of diabetes mellitus and prediabetic states, with the aim of achieving targets for BGL, lipids, waist circumference and weight. Consultation with a qualified dietician is highly recommended.

Principles of dietary management in diabetes:

• patient is encouraged to keep a detailed food diary in the early stages of their management and if BGL or weight management is an issue

• low saturated fats

• low-glycaemic-index, high-soluble-fibre carbohydrates

• avoid sugary sweets and soft drinks

• emphasis on fresh whole foods, fruit and vegetables and whole grains

• quality protein sources such as soy foods, organic lean meat or chicken, including at least two meals of oily fish per week (salmon, herring, trout, mackerel, sardines); protein should contribute 10–20% of total energy

• portion control

• regular mealtimes during the day

• limit alcohol to one to two drinks per day maximum, with at least two alcohol-free days a week.

Glycaemic index

The glycaemic index (GI) is a ranking of carbohydrates from 0 to 100, based on the extent to which they raise blood glucose levels after ingestion. High-GI foods (white bread, white rice, potatoes) are rapidly digested and absorbed, and result in higher fluctuations of BGL. A predominantly high-GI diet is associated with a higher risk of obesity, type 2 diabetes and cardiovascular disease. Low-GI foods (most fruits and vegetables, whole grains) cause gradual increases in BGL and insulin levels. The presence of soluble fibre reduces the GI of foods by slowing the gastric emptying rate.

A low-GI diet is recommended for primary prevention of type 2 diabetes and cardiovascular disease, in the management of diabetes and prediabetes and for maintenance of general health. A low-GI diet is part of the story, but the glycaemic load is an important marker of how good or bad a food is for blood glucose control, insulin level and diabetic control. The high GI of foods such as parsnip and dates is offset by their high dietary fibre content, meaning that they have a relatively low total glycaemic load. Hence, although many fruits and vegetables have a relatively high sucrose content, they are nevertheless good for diabetics because of their high natural levels of fibre. Sucrose, a form of sugar made up of glucose and fructose, has a moderate GI. Many commercially produced foods contain high levels of refined sucrose (sugar) but very low fibre content and therefore have a high glycaemic load. Hence, it is not ‘sugar’ per se that is problematic for diabetics, but refined sugar. Many commercially produced fruit-juice drinks and foods are labelled as having ‘no added sugar’ but actually have high levels of sucrose through the addition of things such as fruit juice concentrate or corn syrup. Many ‘low-fat’ foods also masquerade as being healthy for diabetics but often have high levels of refined sucrose. It is therefore important for patients to cultivate their ability to read and understand the contents on food labels in order to understand what they are eating. A dietician can help with this.

FIGURE 26.4 Glycaemic index chart for some common foods

Exercise

Regular exercise improves metabolism of glucose and lipids. If a patient is aged over 40 and leads a sedentary lifestyle, has a family history of heart disease and/or other risk factors for cardiovascular disease, a medical assessment including stress ECG is advisable before a specific exercise program is recommended.

For a walking program, a pair of correctly fitting shock-absorbing sports shoes and diabetic socks is an important prerequisite. Commence with brisk walking for 30–45 minutes every day, and build up intensity and time gradually as exercise tolerance improves.

Resistance (weight) training increases basal metabolic rate, maintains lean muscle mass, improves muscle glycogen uptake and reduces the risk of osteoporosis.

Avoidance of tobacco smoke

Apart from stating the obvious—that every patient needs to be encouraged to avoid tobacco smoke—the increased risk for people with diabetes makes it an imperative because of its strong association with cardiovascular disease and microvascular complications of diabetes. Patients should be offered counselling and advised, if necessary, on nicotine replacement, hypnotherapy and acupuncture to help reduce craving.

Supplements

There is no international consensus on a protocol of supplements for diabetes management, and decisions will need to be made on an individual basis. The following guide will assist decision-making and can form a part of initial integrative lifestyle and nutritional management.

Fish oil

Omega-3 polyunsaturated fatty acid (PUFA) supplementation in type 2 diabetes lowers triglycerides and VLDL cholesterol, but may raise LDL cholesterol (although results were non-significant in subgroups) and has no statistically significant effect on glycaemic control or fasting insulin. Trials with vascular events or mortality-defined endpoints are needed. No adverse effects of the intervention were reported.⁹

Recommendation: 2–3 g per day.

Multivitamins

A high-quality daily multivitamin and mineral may be the most convenient and cost-effective way to ensure compliance and adequate daily vitamin intake.

Antioxidants

Patients with type 1 diabetes have a higher level of free radicals than non-diabetics.

Vitamin C

People with diabetes, both type 1 and type 2, have lower levels of Vitamin C. Vitamin C can improve glucose tolerance in type 2 diabetes.

Recommendation: 1–2 g vitamin C per day.

B vitamins

Vitamin B₁—correction of thiamine deficiency in experimental diabetes by high-dose therapy with thiamine and the thiamine monophosphate prodrug, benfotiamine, was found to prevent multiple mechanisms of biochemical dysfunction: activation of protein kinase C, activation of the hexosamine pathway, increased glycation and oxidative stress. Consequently, the development of incipient diabetic nephropathy, neuropathy and retinopathy was prevented. Both thiamine and benfotiamine produced other remarkable effects in experimental diabetes: marked reversals of increased diuresis and glucosuria without change in glycaemic status. High-dose thiamine also corrected dyslipidaemia in experimental diabetes—normalising cholesterol and triglycerides. Dysfunction of beta-cells and impaired glucose tolerance in thiamine deficiency, and suggestion of a link of impaired glucose tolerance with dietary thiamine, indicates that thiamine therapy may have a future role in prevention of type 2 diabetes.¹⁰

Vitamin B₃ (nicotinamide)—500 mg daily for a month, followed by 250 mg daily helps reduce BGL in some diabetics. By the time insulin-dependent diabetes mellitus (IDDM) is diagnosed, 80–90% of pancreatic beta islet cells have already been destroyed. Nicotinamide has been shown to protect pancreatic beta cells from inflammation leading to their destruction and to improve remaining beta cell function after the onset of IDDM.^11,¹² The extended release form has a lower incidence of flushing as a side effect. Higher doses may cause insulin resistance and increase fasting blood glucose in patients with non-insulin-dependent diabetes mellitus (NIDDM), so it should be used with caution in this group of patients.

Recommendation: recently diagnosed IDDM: 1500–2000 mg extended-release nocte. NIDDM: use only with caution, monitor requirement for hypoglycaemic agents and fasting BGL.

Vitamin B₆—low levels of vitamin B₆ are common in people with type 2 diabetes.

Recommendation: 50–100 mg daily.

Chromium

Chromium is an essential trace mineral, and a key component in glucose tolerance factor. It is essential for normal carbohydrate metabolism and insulin sensitivity, and reduces insulin resistance. Chromium also inhibits the pro-inflammatory cytokine tumour necrosis factor alpha, which reduces the activity of insulin. It seems to be more effective in non-insulin-dependent diabetes mellitus (NIDDM) than in IDDM.

Recommendation: There is strong evidence that 200–1000 μg of chromium picolinate daily in two divided doses improves glycaemic control. Biotin might enhance its effects, but this combination requires further study.

Magnesium

Magnesium deficiency is common in people with diabetes and may be protective against the development of early-stage type 2 diabetes in individuals with normal renal function.¹³

Recommendation: Increase consumption of major food sources of magnesium, such as whole grains, nuts and green leafy vegetables. Supplement where renal function is normal and diet is deficient.

Zinc

Zinc deficiency is common in type 1 and type 2 diabetes. Diabetes decreases zinc absorption and increases urinary excretion, decreasing total body zinc. It is particularly common in vegetarians. Production, storage and secretion of insulin requires zinc. Zinc supplementation therefore is a reasonable strategy for prevention of zinc deficiency in diabetes.¹⁴ Zinc used as therapy in obese women with normal glucose tolerance has been shown to decrease insulin resistance.

Recommendation: 30 mg elemental zinc daily (check renal function).

Gymnema sylvestre suppresses perception of ‘sweet’ taste and reduces sweet craving.¹⁵ It reduces intestinal absorption of glucose and inhibits active glucose transport in the small intestine, stimulates insulin secretion and increases the number of islets of Langerhans and pancreatic beta cells.¹⁶ Doses of hypoglycaemic medication may need to be adjusted, as it can reduce BGL.

Dose: When used to regulate BGL, to be given in divided doses with meals. Extract standardised to contain 24% gymnemic acids: 400–600 mg/day. Liquid extract (1:1): 3.6–11.0 mL/day.

Fenugreek

Fenugreek has been used traditionally to regulate BGL levels by delaying glucose absorption and enhancing its utilisation.¹⁷ It has mild hypoglycaemic, lipid-lowering and anti-inflammatory effect. Forms and treatment regimens vary. Doses of hypoglycaemic medication may need to be adjusted, as it can reduce BGL.

Dose: 50–100 g seed daily in divided doses with meals, or 1 g/day ethanolic seed extract.

Evening primrose oil

Evening primrose oil is useful in treating mild to moderate diabetic neuropathy.¹⁸ It may be combined with fish oil.

Dose: 360–480 mg gamma linoleic acid (GLA) (equivalent to 4–6 × 1 g capsules per day).

Cinnamon ¹⁹

Cinnamon has been used for thousands of years to treat diabetes and other conditions. The aqueous extract appears to activate the insulin receptor by multiple mechanisms, and also increases glycogen synthase activity. Overall, there is moderate evidence that cinnamon lowers blood glucose levels. Its effect on HbA_1c appears negligible, but long-term studies are required to properly evaluate this outcome.

ACUPUNCTURE

Acupuncture may help improve local microcirculation and delay progression of neurological or circulatory complications such as retinopathy, intermittent claudication and peripheral vascular disease.

MENTAL HEALTH, STRESS AND DIABETES

Diabetes can predispose a patient to poor mental health, and poor mental health can predispose patients to diabetes as well as increasing comorbidity, negatively affecting the person’s lifestyle and also making it harder for patients with diabetes to cope with their condition.

People living with diabetes have at least double the risk of depression compared with individuals without diabetes.²⁰ Depressive symptoms in initially non-diabetic adults have also been shown to be predictive of later development of type 2 diabetes,²¹ with a 63% increased risk of diabetes in subjects demonstrating depressive symptoms (including recent fatigue, sleep disturbance, feelings of hopelessness, loss of libido and increased irritability) at baseline.

Psychological stress can precipitate a range of autoimmune conditions including type 1 diabetes ²² through the process of dysregulation of the immune system. Stress increases blood sugar and fat levels and so can also destabilise type 2 diabetes and increase the chances of diabetic complications such as heart disease. It can also contribute to the destabilisation of diabetes via secondary effects such as:

• making it more likely that the person will not follow a healthy and disciplined lifestyle

• leading to poorer maintenance and monitoring

• increasing susceptibility to infections or other illnesses.

Research on diabetes shows that stress management leads to a significantly better level of diabetic control and lower rate of complications,²³ making for more stable control, healthier lifestyle and better compliance with treatment and monitoring. Stress management is therefore a core element in diabetes management.

Chronic or long-term activation of the stress response leads to high ‘allostatic load’,²⁴ a form of prolonged wear and tear on the body. High allostatic load is found in chronic stress and anxiety, and depression, and is associated with poor immunity, acceleration of atherosclerosis, ‘metabolic syndrome’ and chronically high cortisol levels. Stress in the workplace has been shown to be an important risk factor for metabolic syndrome.²⁵ This is thought to be associated with high basal secretion of cortisol.

YOGA

A systematic review of studies examining the effect of yoga on diabetes suggest beneficial changes in several risk indices, including glucose tolerance and insulin sensitivity, lipid profiles, anthropometric characteristics, blood pressure, oxidative stress, coagulation profiles, sympathetic activation and pulmonary function, as well as improvement in specific clinical outcomes.²⁶ Yoga may improve risk profiles in adults with type 2 diabetes, and may have promise for the prevention and management of cardiovascular complications in this population. However, the limitations characterising most studies preclude any firm conclusions being drawn.

MEDICATION

Trial of lifestyle measures first

If a 6-week trial of lifestyle and nutritional measures fails to control blood glucose levels in an asymptomatic person with type 2 diabetes, pharmaceutical oral hypoglycaemic agents may be indicated. Start with small doses and increase weekly, depending on response.

Oral hypoglycaemic agents

If symptomatic or if BGL at diagnosis is > 20 mmol/L, medication is indicated to reduce BGL and relieve symptoms at the time of diagnosis.

• Metformin—first-line for the overweight person with type 2 diabetes. Raised serum creatinine is an absolute contraindication. Caution in patients with heart or liver disease or heavy alcohol intake. Usual starting dose is 500 mg twice a day or 850 mg once daily. Gradually increase by 500 mg per day at weekly intervals or 850 mg per day at intervals of 2 weeks as tolerated and based on the blood glucose response.

• Sulfonylureas (tolbutamide, gliclazide)—stimulate the pancreas to produce insulin. Special care is needed in the elderly with regard to precipitating hypoglycaemia. May cause weight gain, nausea, diarrhoea.

• Glitazones—reduce insulin resistance. Pioglitazone and rosiglitazone can be used with insulin or other hypoglycaemic agents. However, there have been reports of rates of myocardial infarction increasing by 40% with rosiglitazone, and both rosiglitazone and pioglitazone have been reported to precipitate heart failure, cause peripheral fractures and possibly cause or worsen macular oedema.

INITIATION OF INSULIN

The decision to commence insulin, and the choice of insulin to prescribe, depends on the level of glycaemic control, and the patient’s eating and exercise patterns.

The types of insulin include:

• rapid-onset, fast-acting insulin (Lispro and Aspart)—onset of action within 1–20 minutes. Peaks after 1 hour and lasts 3–5 hours. Patient must eat immediately after injecting

• short-acting insulin (neutral)—peak effect at 2–4 hours, and lasts for 6–8 hours

• intermediate-acting insulin (Isophane)—begins to work after about 90 minutes, peaks at 4–12 hours and lasts for 16–24 hours

• mixed insulin—pre-mixed combination of either a rapid-onset, fast-acting or a short-acting insulin, and intermediate-acting insulin. The numbers written after the brand name show the mix of the two types of insulin. For example, Humulin 30/70 contains 30% short-acting insulin and 70% intermediate-acting insulin. Mixtard 50/50 contains 50% short-acting insulin and 50% intermediate-acting insulin

• long-acting insulin (insulin glargine or insulin detemir)—releases insulin into the bloodstream at a fairly constant rate over 24 hours.

TYPE 1 DIABETES

Initial assessment by an endocrinologist is advisable, to establish a program of shared care and to arrange diabetes education.

• Insulin initiation is most commonly with Isophane insulin twice daily (or Isophane Insulatard for pens) subcutaneously at a dose of 5 units b.i.d. (or 6 units for a pen that delivers in multiples of 2 units) if random blood glucose level is below 15 mmol/L.

• Starting dose is 10 units b.i.d. if blood glucose is 15 mmol/L or above.

• Insulin to increase by 2 units b.i.d until blood glucose readings are under 10 mmol/L.

• Insulin can be increased by 4 units b.i.d. if blood glucose level remains above 17 mmol after 48 hours of insulin therapy.

• If daily insulin requirements increase to 20 units in a single dose of intermediate-acting insulin, mixed insulin may be introduced.

• A combination of pre-prandial soluble (Actrapid) insulin, given with a background of medium-/long-acting insulin taken at bedtime may give greater flexibility of mealtimes and food types.

TYPE 2 DIABETES

Establish that lifestyle measures have been adequate, and exclude intercurrent infection or other complicating medical conditions.

While intensive lifestyle management and/or oral hypoglycaemic agents are first-line treatments for type 2 diabetes, many patients with type 2 diabetes will eventually fail to respond adequately to oral hypoglycaemic drugs and will require insulin therapy.

The United Kingdom Prospective Diabetes Study (UKPDS)²⁷ showed that most people with type 2 diabetes will experience progressive pancreatic beta-cell dysfunction despite excellent control, and become refractory to oral hypoglycaemic agents.

Some patients will require insulin early in the course of the disease if they fail to respond to lifestyle management and oral hypoglycaemic agents. This may indicate that they in fact had type 1 diabetes.

People with type 2 diabetes requiring insulin can often be managed with a single daily dose of intermediate- or long-acting insulin added to their oral hypoglycaemic schedule. Quick-acting insulin is not necessarily needed.

A regimen of intermediate-acting insulin (10 units) at bedtime in combination with daytime oral drugs is usually acceptable to patients, simple to start and results in rapid improvement in glycaemic control.²⁸

The aim is to ‘start low and go slow’. Doses can be increased in increments of 10–20% at intervals of 2–4 days.

The basal insulin can be isophane or glargine. Glargine may cause less hydroglycaemia than isophane. In the long term, metformin can be continued or added, to reduce insulin resistance (and dose) and to help reduce weight gain.

Insulin can be delivered in syringes, pens or insulin pumps.

Sites for insulin injections:

• abdominal wall—generally fastest and the most uniform rate of absorption

• legs—slowest absorption (unless exercising); acceptable site

• arms—not recommended; injections should be subcutaneous.