Adjusting diabetes regimens in Diabetes

Self-measurement of blood glucose offers the diabetic patient and his or her doctor a unique opportunity to restore glucose levels to within, or at least near, the physiological range. What is clear is that both need to understand the various factors that influence glucose levels in the blood, i.e. food intake, physical activity and insulin supply. Self-measurement of blood glucose allows the individual to interpret theses variables and learn, through experimentation, the effect of a change to one or more. The outcome of such a programme of self-experimentation in association with careful review is almost always marked improvement of control.

This article details the approaches used by the Diabetes Unit, Princess Margaret Hospital, Christchurch, New Zealand in instructing patients in self-management of their insulin replacement regimens. The essential aspect underlying the basic programme is knowledge, not only knowledge by the patient, but of the attending health professional.

It is essential that the reader is familiar with the pharmacokinetics of different insulins and the factors influencing absorption (Berger et al. 1982), as these are fundamental to the treatment of insulin-dependent diabetics. In addition, new advances and changes in treatment impose a need for regular up-dating.

1. Understanding the Physiological Basis of Glucoregulation

In the past many health professionals and their patients have accepted glycaemic control that today is considered not appropriate. One of the contributors to this problem has been lack of awareness of the non-diabetic individuals. Very often in the past patients have been reassured that their measured glucose levels, for example around 10 mmol/L, are nearly normal when in fact such a value is around 2 times normal. This Diabetes Unit has adopted a rigid policy of ensuring that its patients are well aware of the normal range of blood glucose at different times of the day. All results obtained form self-measurement of blood glucose are then interpreted with reference to this normal range. Because many health professionals do not have a good understanding of the variation of glucose throughout the 24-hour period

Table 1.

The Basic requirements for good control in diabetes

  1. Competent support from health professionals
  2. patient knowledge in all aspects of diabetes management
  3. good understanding of physiological mechanisms for glucoregulation, especially as they relate to insulin release and action
  4. understanding of nutrient requirements in diabetes and the importance of normal body weight
  5. awareness of the mechanisms of action and pharmacology of insulin and oral agents
  6. awareness of the effect of exercise on glucoregulation
  7. Clear identification of treatment goals.

It can be seen clearly that in the fasting state before breakfast, values are usually around 4 to 5 mmol/L. After ingestion of food, glucose levels rise slightly, but seldom exceed 7.5 mmol/L.

In fact many subjects show a rise in glucose of less that 1 mmol/L postprandially. These data highlight the effectiveness of the glucoregulatory process. A number of different factors are responsible for this glucoregulation, but insulin is clearly one of the most important.

This unit has found that once a diabetic patient understands this relationship between insulin, food and glucose control, he or she is in a position to choose as insulin replacement regimen that is rational and physiologically appropriate.

2. Choosing a physiological Insulin Replacement Regimen

There is a physiological requirement for greater amounts of insulin at times of good ingestion and also during the early hours of the morning-approximately after 4 am. This can be achieved by a multiple subcutaneous injection regimen or by insulin infusion associated with mealtime pulses.

2.1 Advantages of a Multiple-dose Regimen

Although such regimens may, on the surface, appear inconvenient, they do have distinct advantages in that they give flexibility of mealtimes, relatives simplicity in altering the insulin dosage in accordance with the requirements for that meal, and of course there is the potential for excellent glycaemic control over the whole 24-hour period. Other factors, such as reduction of frequency of hypoglycaemia, inherent flexibility of lifestyle and greater ease in adjusting other variables, e.g. exercise, are reasons why many patients come to adopt such a regimen. One other distinct advantage is that it is easier for the patient to understand which insulin is working at any time of the day, and therefore which insulin needs adjustment. These patients very quickly learn to do their own adjustments, although initially they do need the support of a health professional. We have found that algorithms for insulin adjustment (table II) and stylized diagrams of insulin action are very useful patient aids.

2.2 Alternative Regimens

Nevertheless, many patients do not accept a 4 time-a-day injection regimen and therefore it is essential to provide alternative regimens of either 3 injections per day or, more commonly, a twice-daily regimen where each of the 2 injections comprises rapid and long acting components. Single injection regimens or twice daily insulin regimens not containing a rapid action insulin are not used by this Diabetes Unit in any situation where good diabetic control is considered important. We are of course clearly drawing a distinction between the patient who is motivated and striving for physiological control, and the patient in whom this may be considered not possible or not essential, e.g. elderly persons with other health problems.

Adjusting insulin

Meal-timed injection of rapid-acting insulin

This handout is a guide only to help you adjust your own insulin and achieve more normal glucose levels.

This applies only if your insulin regimes consists of:

  • A rapid-acting insulin (clear) before each major meal, and
  • A long-acting insulin (cloudy) either before your evening meal or as a separate injection before going to bed.

Time of Day

Ideal glucose levels

mmol/L

Your results

Other changes

Other changes

Pre-breakfast

4-5

Too high

Too low

# Evening long acting insulin

$ Evening long acting insulin

Check glucose 2-4am

Check glucose 2-4am

Between 2-4h

After meals

4-8

Too high

Too low

# Meal timed rapid-acting insulin

$ Meal timed rapid-acting insulin

Check exercise

programme, check diet

Before bed

4-8

Too high

Too low

# Meal timed (evening meal) rapid-acting insulin

$ Meal timed rapid-acting insulin

Check exercise

programme

check diet

2-4 am

3-5

Too high

Too low

# Evening long acting insulin

$ Evening long acting insulin

or shift long acting insulin to just before going to bed

Check pre-breakfast levels

General advice

· Most patients using insulin need to blood test only about 3 days each week

· On each testing day at least 3, preferably 4 tests are needed

· Study the daily test profiles and work out ways of improving these

· Make one change at a time only

· Retest over several days and if necessary make another change

· See your doctor if you are unsure what to do

Remember:

If your tests are high, they will not get better by themselves – you need to do something positive

A guide to insulin adjustment for patients on twice daily dose regimens

Adjusting insulin

Twice daily injection of rapid-acting/long acting insulin mixes

This handout is a guide only to help you adjust your own insulin and achieve more normal glucose levels.

This applies only if your insulin regimes consists of:

  • A pre-breakfast injection of a rapid-acting (clear) and a long acting insulin (cloudy) [separate or mixed], and
  • An injection before the evening meal of a rapid – acting and a long acting insulin (separately mixed)

Time of Day

Ideal glucose levels

mmol/L

Your results

Other changes

Other changes

Pre-breakfast

4-5

Too high

Too low

# Evening long acting insulin

$ Evening long acting insulin

Check glucose 2-4am

? Shift evening long acting insulin to before bed

Between 2-4h

After meals

4-8

Too high

Too low

# Meal timed (breakfast) rapid-acting insulin

$ Meal timed (breakfast) rapid-acting insulin

Check diet

Check exercise

programme

Before bed

4-8

Too high

Too low

# Meal timed (evening meal) rapid-acting insulin

$ Meal timed rapid-acting insulin

Check exercise

Programme, check diet

Before evening meal

4-6

Too high

Too low

# Morning long acting insulin

$ Morning long acting insulin

Check exercise

Programme, check diet

2-4 am

3-5

Too high

Too low

# Evening long acting insulin

$ Evening long acting insulin

Check pre-breakfast glucose levels

General advice

· Most patients using insulin need to blood test only about 3 days each week

· On each testing day at least 3, preferably 4 tests are needed

· Study the daily test profiles and work out ways of improving these

· Make one change at a time only

· Retest over several days and if necessary make another change

· See your doctor if you are unsure what to do

Remember:

If your tests are high, they will not get better by themselves – you need to do something positive

Benefits of Multiple-dose Regimens

This Unit attempts to obtain the best possible con­trol in all newly diagnosed insulin-dependent diabet­ics, all young diabetics (less than 40 years), all those with complications, and all pregnant patients with elevation of blood sugar. If twice-daily or 3-times-daily regimens are used, they can result in excellent gly­caemic control provided patients are active partici­pants in the programme and understand their insulin regimens well.

We have realised that less reliance must be placed upon long-acting insulins since these impose prob­lems with inflexibility of lifestyle, requirement for between-meal snacks, and sometimes restrictions on exercise. The Unit’s experience with such regimens of long- and short-acting mixes has therefore been to reduce the amounts of long-acting insulins used and increase relatively the amount of short-act­ing insulins, perhaps contributing to the trend to overall reduction in daily consumption of insulin by insulin-dependent diabetic patients in this region. The present mean daily consumption of insulin by insulin-treated patients in the Christchurch area (Christ­church population 335,000) is 38.2 units. Patients us­ing large amounts of insulin (greater than 50 units day) are almost always on poorly constructed insulin replacement regimens and inevitably undergo a dose reduction when these are altered.

Patients on twice-daily or 3-times-daily regimens are equipped with instruction sheets on how to adjust their own insulin. An example of the sheet available to patients for the twice-daily mixed insulin regimen is shown in table III.

3. Special Control Problems

3.1 Nocturnal Hypoglycaemia

Because patients are very sensitive to insulin at night and frequently receive a long acting insulin either before the evening meal or before supper, they are at risk of developing their lowest level of blood sugar during the early hours of the morning. We require most patients to test their blood sugar at 2am or 3am on some occasion to at least verify that this is not occurring. Patients taking high doses of long-acting insulin are especially at risk. The solution is relatively simple since all that may be required is reduction of the evening dose of long-acting insulin. Any deteri­oration of periprandial glycogenic control can best be prevented by the addition (or increase) of short-acting insulin prior to the evening meal. A further useful alternative, however, is the shifting of the evening long-acting insulin to a later time in the night, such as immediately before going to bed. This has the ef­fect of advancing the peak action of the long-acting of insulin some hours, thus reducing the tendency to nocturnal hypoglycaemia.

3.2 Early Morning Hyperglycaemia

One of the more difficult parts of the day to man­age is the time around breakfast. Blood sugar is often at its highest immediately after breakfast and reaches its peak at mid-morning. This apparent escape of blood sugar control is a reflection of the insulin de­ficiency and inherent insulin resistance at this time of the day. Although good results are not always ob­tained, the situation can be improved dramatically by efficient use of a fast-acting insulin before breakfast and by ensuring that the patient is not insulin defic­ient during the period from 4am to 7am. Rational use of a long-acting insulin the evening before prevents this insulin deficiency occurring.

3.3 Postprandial Hypoglycaemia

Although the fast-acting insulins are absorbed fairly rapidly they are often associated with post absorption hyperinsulinism which may contribute to hypogly­caemia some 3 to 4 hours following injection. Useful techniques that may assist are reduction in the amount of fast-acting insulin that is used, dietary manipula­tion with some emphasis being placed on mid-morn­ing snacks, and careful balance of the exercise pro­gramme. A factor often overlooked is the variability of the absorption of insulin from different injection sites. Much faster insulin absorption can be achieved by injection into the abdomen and this can be en­hanced even further by massage. Increased rapidity of absorption with the consequence of less post absorptive hyperinsulinism should reduce postpran­dial hypoglycaemia and patients who are injecting in the leg or the arm should try changing the injection site to the abdomen.

Blood Glucose Chart

Date

Time

B

L

O

O

D

G

L

U

C

O

S

E

(mmol/L)

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

Normal 5

4

3

2

1

0

Insulin/Tablet

- type

- Dose

Comments

Useful blood testing times

- before breakfast and lunch

- before evening meal

- 1 – 2 hours after meals

Do at least 4 tests on any testing day

Suggested testing days are

-------------------------------------

An example of a flow sheet or patient recording of blood glucose tests in use at the Diabetes Unit, Princess Margaret Hospital, Christchurch.

3.4 Insulin Requirements during Exercise

Many diabetic patients are now becoming involved in vigorous exercise programmes such as marathon running, and the patient, the doctor and other health professionals are having to come to grips with the nutrient and insulin requirements associate with this physical stress. Our experience to date has been too limited to make any generalization apart from finding meal-timed rapid acting insulin injection regimens advantageous because of the reduction in frequency of hypoglycaemia during the exercise

3.5 Pregnancy

The requirement for the very best of diabetic con­trol during pregnancy requires the adoption of one of the more intensive regimens such as 3- or 4-times-a-day injection. These algorithms are as applicable to the pregnant as to the non-pregnant individual.

4. Self-measurement of Blood Glucose

One of the factors essential to good glucose control is self-measurement of blood glucose. If adequate rec­ords of blood glucose measurement are not main­tained, decision-making is impaired. This Unit im­poses fairly rigid requirements on insulin-treated patients with respect to self-measurement of blood glucose and patients are required to test on any given testing day or 4 occasions over the waking period. Patients are then required to interpret these results and make changes in the interests of good control.

Comprehensive records are maintained in order to assess the decision-making skills of the individual.No urine testing for glucose is asked of patients who are doing self-measurement of blood glucose, but urinary ketones are still needed at times of illness or poor control.

5 Conclusions

An excellent understanding by patients and their health advisers is essential for good glycaemic control in diabetes mellitus. Self-measurement of blood glu­cose allows the patient to interpret his or her control and make changes with the support of a health professional. Insulin regimens need to be appropriate to the physiological situation if they are to result in good physical control.

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