Latent auto immune diabetes of adulthood (LADA)

LADA has an auto-immune aetiology like T1DM but tends to present later in life than classical T1DM and often runs a more indolent course, with a slow insidious onset. Indeed some authorities only recognise LADA as a variant of T1DM. Historically, also known as 'type one and a half diabetes'.

Insulin therapy

What are the advantages of a basal bolus regimen?

Most newly diagnosed individuals with LADA will be started on a 'QDS' (basal bolus) insulin regimen consisting of a once daily long acting insulin (normally an analogue such as insulin-glargine (Lantus) or insulin detemir (Levemir) and three injections of prandial insulin such as insulin aspart (Novorapid), insulin glulisine (Apidra) or insulin lispro (Humalog).

Are there circumstances where a twice daily biphasic insulin may be more appropriate?

In those who are very reluctant to inject insulin at all a bd regimen is sometimes used.

The major draw back of twice daily mixed insulin regimens is that the longer acting component tends to 'peak' five to six hours after injection. This mandates eating a midday meal within a relatively narrow time window and at night leads to increased risk of nocturnal hypoglycaemia and often mandates a pre-bed time snack to reduce this risk.

For these reasons, it is often more difficult to achieve a good HbA1c without unacceptably high frequency of hypoglycaemia with twice daily mixed insulin regimens.

When is continuous subcutaneous insulin infusion therapy, also known as 'pump therapy', indicated?

Continuous subcutaneous insulin infusion therapy (CSII) therapy involves the patient wearing a pump device connected to a permanently indwelling subcutaneous needle.

Soluble insulin is continually delivered at a pre-set basal rate which can be programmed to vary at different times of day. The patient then triggers a bolus each time they eat. The size of the prandial bolus being selected by the patient.

CSII is expensive and its availability on the NHS, in adult practice, is tightly restricted and patients must fulfil a number of criteria specified by NICE.

Patient education

Who should be taught self-monitoring of glucose levels?

All newly diagnosed patients with LADA need to be taught home blood glucose monitoring, encouraged to do so two to four times a day and keep records of the results in order to inform discussion with their diabetic team and also to inform their own self-management decisions.

What topics should be covered in general diabetes education at presentation?

This is a large and important subject and it is important that the diabetes specialist nurses spend considerable time with newly diagnosed T1DM covering several important topics.

These include hypoglycaemia recognition and self management, sick day rules, injection sites, driving, diet, adjusting insulin doses, use of insulin injection devices (including storage of insulin), changing cartridges and needles, recognising potential injection device failure and, for female patients, contraception and pre-pregnancy planning.

 

What is DAFNE?

DAFNE, or dose adjustment for normal eating, is a system for adjusting insulin doses based on food intake and prevailing blood glucose concentrations.

It is not suitable for all patients as it requires the patient to perform several blood glucose measurements each day and requires a high degree of commitment from the patient to assiduously testing, adjusting and recording.

The system is taught on a five day long non-residential course where trained DAFNE educators work (and eat!) with the patients intensively all week long. The basic principles of DAFNE involve the patient first discovering what their basal insulin requirement is by achieving stable blood sugars across the night and across a carbohydrate-free meal time.

They next learn carbohydrate counting - a system of estimating carbohydrate content of common food stuffs - and then calculate the required ratio of units of fast acting insulin to carbohydrate content which can be different for each meal.

There is also a system for correction doses of insulin for unexpectedly high blood sugar readings.

 

How are patients taught to adjust their insulin doses?

Adjusting insulin doses is an essential part of self-management for patients with LADA.

While a minority of patients take fixed doses of insulin regardless of dietary intake and variations of physical activity this approach rarely produces good glycaemic control and, especially for patients on basal bolus regimens, it means that the patient is not realising much of the potential benefit of the flexibility of such a regimen.

It is usual for the dose of basal insulin to be kept fairly constant and most of the adjustments to be made on the prandial insulin. Some experienced patients learn empirically how much rapid acting insulin they need with meals of varying size and composition. Other patients develop a habit of testing their blood sugar and reacting to the result by adjusting the size of the next dose of rapid acting insulin, sometimes giving extra doses in between meals.

However, many would discourage this approach as it tends to promote a relatively unstable blood sugar oscillating between low and high blood sugars.

Formal systems for dose adjustment include carbohydrate counting, DAFNE which, although based in carbohydrate counting, is a much more sophisticated approach.

Another approach used by some patients is to record blood sugars and dietary intake and to regularly consult with their diabetes specialist nurse who will advise on future adjustments to insulin doses based on the results. This system has the advantage of being both educational and therapeutic but is quite labour intensive.

What are the recommended precautions around driving?

The mainstay of safe driving in people with diabetes is the avoidance, recognition and appropriate management of hypoglycaemia.

Thus, patients are advised to check their BM before getting in the car and to not set off if it is low until this has been rectified, to stop and check BM periodically during long journeys and to keep a source of rapidly absorbable carbohydrate, such as dextrose tablets, in the car.

If the patient does feel hypoglycaemia coming on they should pull over at the side of the road as soon as it is safe to do so, check their BM, ingest rapidly absorbed carbohydrate followed by a source of longer-acting carbohydrate and not proceed until their BM is back to a safe level and they feel well enough to continue.

The DVLA regularly re-assess the driving-safety of insulin-treated patients with diabetes by questionnaire to the patient and their doctor. The medical questionnaire includes an assessment of the patients knowledge of the above guidance.

Patients with significant hypoglycaemia unawareness may have their licence suspended by the DVLA for a period until some awareness has been restored.

Read more on driving

 

What is the standard advice around alcohol consumption?

Somewhat counter-intuitively to many patients, alcohol tends to lower rather than raise blood sugar levels.

This effect is largely due to inhibition of hepatic gluconeogenesis. Thus patients should be educated about this effect, should check their blood sugar after imbibing alcohol and may even need to reduce the dose of prandial insulin taken with food before an evening in the pub.

Read more on drinking

 

What are sick day rules?

Sick day rules are guidelines for patients with diabetes providing advice on how to manage blood sugars and insulin/tablets during times of illness, especially illnesses that lead to reduced food intake and/or vomiting.

During these times, the cardinal advice is that patients should NEVER STOP THEIR INSULIN.

Insulin requirements often actually rise during inter-current illness, even if food intake has significantly fallen. Thus, patients are advised to regularly check BMs (two to four hourly), continue their regular doses of insulin, counter any falling blood sugars with frequent small sips of sugary drinks and maintain a high fluid intake (ideally 3 litres per day).

Read more on sick day rules and T1DM.

 

What does good dietetic advice include?

Dietary advice for people with diabetes should be little different from general healthy eating advice.

Specifically, avoidance of refined sugars, reduction of saturated animal fats, the majority of calories coming from complex carbohydrates, five portions of fresh fruit and vegetables per day and a caloric intake aimed at maintaining steady weight (~2,000 cal per day for women and ~2,500 for men).

Much of this advice is summarised on the 'eatwell plate'. One particular aspect of relevance to patients treated with insulin is the carbohydrate content of meals as this is a major determinant of prandial insulin requirements. This can be assessed by a system known as carbohydrate counting.

 

What is carbohydrate counting?

Carbohydrate counting is a system for estimating the carbohydrate content of a meal by eye. It requires skill and takes time to learn. However, with practice it becomes a very useful to self-management tool.

The system involves patients learning to recognise standard quantities and types of food-stuff which can be done in practical sessions with dieticians or from books containing photos of plates of food.

Examples include 1 medium size boiled potato = 10 g carbohydrate. One slice white bread (standard thickness) = 15 g carbohydrate. With experience, the patient also learns how much prandial insulin they require per 10 g carbohydrate and thus after inspecting a plate of food can then accurately estimate the required dose of prandial insulin to take with that meal.

The system is an important component of the DAFNE system.

 

What are 'correction doses'? 

A correction dose is a dose of insulin given when the patient feels their blood glucose is too high and they want to give a bolus of soluble insulin to bring it back to target. A typical target value might be 8 mmol/L.

The correction factor is calculated using the 'hundred rule'. This works by dividing the patient's total daily of insulin in to 100. Thus, a patient taking 50 units of insulin per day will have a correction factor of two i.e. one unit of soluble insulin will bring their blood glucose down by 2 mmol/L.

For example, if their random blood glucose is 18 mmol/L, they want to bring it down by 10 mmol/L and thus they will need to give five units of soluble insulin.

However, we often discourage patients from using too many correction doses, preferring that they focus on getting the dose of basal insulin right for them. Ideally this should be by dose-adjustment with meals (e.g. by carbohydrate counting). 

Annual Review

What areas should be covered in the consultation?

 The aim of the annual review is to screen the patient for the presence of established complications and assess their risk factors for future complications.

Areas covered in the consultation depend on the patient’s history but should normally include:

1. Review of the glucose monitoring diary and or glucometer.

2. Assessment of the frequency of hypoglycaemia; whether the patient has adequate warning symptoms; does the patient know how to treat their hypos, and are there any obvious precipitating factors?

3. What insulins and what doses are being taken?

4. What other medicines are being taken, especially focussing on primary and secondary cardiovascular prevention (statins, aspirin, ACE inhibitors)?

5. Is the patient a smoker?

6. Is their weight changing? Are they overweight?

7. How is their general health?

8. For all women of child bearing age, advice on pre-pregnancy measures is necessary and a discussion of use of effective contraception and avoidance of unplanned pregnancy.

9. An opportunity for the patient to discuss specific problems and concerns.

10. With male patients, enquire about erectile dysfunction.

What physical examination should be performed?

As a minimum this should always include physical examination of feet (foot pulses, two-modality sensory screening including 10g monofilament and vibration sensation), blood pressure, injection sites and retinal screening (ideally by digital retinal photography scored by an ophthalmologist or accredited retinal grader).

What biochemical investigations should be performed?

Biochemical assessment of HbA1c, ACR, renal function and fasting lipids including cholesterol and triglycerides should be undertaken.

What else?

Patients should also be offered a review by a diabetes nurse specialist and dietician. 

Structured education

What is structured education?

Standard 3 of the NSF states that all people with diabetes will receive a service that encourages partnership and decision-making, supports them in managing their diabetes and helps them to adopt and maintain a healthy lifestyle.

Structured education is one of the key interventions needed to achieve Standard 3. There are several structured education systems available.

 What structured education systems are available?

 DAFNE (Dose adjusted for normal eating). 

Diabetesbible is for health professionals