Adjusting insulin dose.. glucose control
David Kinshuck
Adjusting
insulin dose pages from DAFNE
What is good blood glucose control?
Good control of blood glucose is needed to
- feel well
- avoid minor infections caused by high blood glucose levels
- avoid severe hypos avoid diabetoketoacidosis
- to prevent / delay complications
- if pregnant to ensure a healthy baby
What is good blood glucose control?..'targets'
When your test your own blood glucose you need to aim for detail , and aim for
- 5-7.0 mmol/l on waking
- 4-7.0 mmol/l before meals and other times of the day NICE 15
- at least 90 minutes after a meal 5-9 mmol/l (except if pregnant)
- bedtime levels..discuss with team
This will keep blood glucose levels as near to the normal range as possible
without causing problems such as hypos.
Occasionally, you may find that your blood glucose reading is high, e.g.
13 mmol/l. As long as you fell well and it returns to an acceptable
level when corrected, this unlikely to cause any harm.
HbA1c (Gylcated Haemoglobin)
See Glucose sticks to the
red blood cells and tissues of the body. The higher the blood glucose, the
greater amount of glucose that attaches to the blood cells and tissues. The
more glucose that is attached, the greater the risk of diabetic complications.
HbA1c measures the amount of glucose attached to the red blood cells The
HbA1c gives a good guide to the blood glucose level over the previous 8-10
weeks. It is used as a measure of long-term measure of diabetic control.
The usual result in someone without diabetes is 20-42mmol/l (4.0-6.0%).
We believe the best result in diabetes is 42-53mmol/mol (6.0-7.0%). At this term most long
term complications can be prevented, whilst at the same time avoiding severe
hypos (hypoglycaemia). Below this level there is a higher risk of a bad hypos.
Above this level here is an increased risk of complications. Before conception
and during pregnancy, slightly lower levels are preferred.
The HbA1c is not the same as the average blood glucose nd is always slightly
lower. For example, someone who has a blood glucose ~17mmol/l with have an
HbA1c of ~120mmol/mol (13%).
Here is how they relate (and see
convertor):
| blood
glucose range mmol/l |
HbA1c |
IFCC-HbA1cmmol/mol |
| under 7mmol/l (non-diabetic) |
less than 6 |
42 |
| mostly under 10 mmol/l |
6-7% |
42-53 |
| frequently over
10 mmol/l |
8-12% |
64-108 |
| mostly over 17 mmol/l |
more than 13% |
120 |
Diaries
It is useful to record your blood glucose results in a diary, along with
carbohydrate intake and insulin dosage, and exercise level. This is a way
for you to monitor your control. It will help you choose the right dose of
insulin in different situations and reflect on particular results. If you
are outside the target range, you will need to adjust
your insulin dose.
How to test your blood glucose level
Most people do not know what their actual blood glucose level is at any
time purely by the way they feel, except in extreme situations (e.g. very
high and low levels). Therefore, if you are aiming to keep your blood glucose
level close to normal, you need to monitor it. Testing
When to test
You only need to test your blood glucose level if the result is to be used
to make a decision. Self-monitoring is important to:
- find out your current blood glucose level
- recognise and avoid hypoglycaemia
- work out the dose of quick-acting insulin before meals
- help achieve ideal blood glucose control
Test your blood glucose each day
- before breakfast (or when you get up if you do not eat breakfast)
- before meals and snacks
- before bed
- before driving and every 90 minutes driving
- sometimes before and after exercise
- feeling unwell
- to confirm hypoglycaemia
Testing for Ketones
It is important to test for ketones when (see)
- blood glucose levels are consistently over 13 mmol/l
- any glucose reading is above 17mmol/l (even if this is unusual)
- if you fell unwell and have symptoms of diabetoketoacidosis
How to test for ketones
- always have testing strips at home ready to use
- use Ketostix testing strips dipping them in urine and then wait for 15
seconds and compare the colour to the chart
- there are also blood sensors that are useful
Shift work
This is a major challenge; ideally control your diabetes with regular shifts
first before changing your shifts. It is much easier now with new
insulins or pumps.
Driving
If you drive for your living you may have to compromise and have higher
glucose levels. This is a decision you should make with your nurse and doctor.
Unfortunately if you have high glucose levels they can damage your eyes and
kidneys etc. HGV drivers have to give up their HGV licence if they need insulin.