Insulin

Principles of insulin therapy

To provide sufficient insulin throughout the 24 h to cover basal requirements
To deliver higher boluses of insulin in an attempt to match the glycemic effect of meals

Frequently used regimens

Two injections daily of a mixture of short and intermediate-acting insulins (before breakfast and the main evening meal)
Three injections daily using a mixture of short and intermediateacting insulins before breakfast; short-acting insulin alone before an afternoon snack or main evening meal; intermediate-acting insulin before bed; or variations of this
Basal-bolus regimen of short-acting insulin 20–30 min before main meals (e.g. breakfast, lunch and the main evening meal); intermediate or long-acting insulin at bedtime
Basal-bolus regimen of rapid-acting insulin analog immediately before main meals (e.g. breakfast, lunch and main evening meal); intermediate- or long-acting insulins at bedtime, probably before breakfast and occasionally at lunchtime
Insulin pump regimes are regaining popularity with a fixed or variable basal dose and bolus doses with meals

None of these regimens can be optimized without frequent assessment by BG monitoring

Daily insulin dosage

Daily insulin dosage varies greatly between individuals and changes over time. It therefore requires regular review and reassessment

Dosage depends on many factors such as

Age
Weight
Stage of puberty
Duration and phase of diabetes
State of injection sites
Nutritional intake and distribution
Exercise patterns
Daily routine
Results of BG monitoring (and glycated hemoglobin)
Intercurrent illness

Guideline on dosage

During the partial remission phase the daily insulin dose is often <0.5 IU/kg per day
Prepubertal children (outside the partial remission phase) usually require 0.7–1.0 IU/kg per day
During puberty, requirements may rise substantially above 1 IU/kg per day

The ‘correct’ dose of insulin is that which achieves the best attainable glycemic control for an individual child or adolescent

Distribution of insulin dose

The distribution of insulin dose across the day shows great individual variation

Children on twice-daily regimens often require more (perhaps two-thirds) of their total daily insulin in the morning, and less (perhaps one-third) in the evening
On this regimen approximately one-third of the insulin dose may be short-acting insulin and approximately two-thirds may be intermediate-acting insulin, although these ratios change with greater age and maturity of the young person
On basal-bolus regimens, night-time intermediate-acting insulin may represent 30–50% of total daily insulin: 50–70% as rapid or short-acting insulins divided up between three to four pre-meal boluses (when using rapid-acting insulin for pre-meal boluses, the proportion of basal insulin may be higher)

Insulin dose adjustments

Soon after diagnosis

Frequent advice by members of the diabetes care team on how to make graduated alterations of insulin doses is of high educational value
Insulin adjustments should be made until target BG levels are achieved
If frequent BG monitoring is not possible, urinary tests are useful especially in the assessment of nocturnal control

Later insulin adjustments

On twice-daily insulin regimens, insulin dosage adjustments are usually based on recognition of daily patterns of BG levels over the whole day or a number of days, or in recognition of glycemic responses to food intake or energy expenditure
On basal-bolus regimens, flexible or dynamic adjustments of insulin are made before meals and in response to frequent BG monitoring. The new analogs may require postprandial BG tests to assess their efficacy

Health care professionals have the responsibility to advise parents, other care providers and young people on adjusting insulin therapy safely and effectively. This training requires regular review, reassessment and reinforcement

Advice

Elevated BG level before breakfast increase pre-dinner or pre-bed intermediate or long-acting insulin (BG tests during the night might ensure that this change does not result in nocturnal hypoglycemia)
Rise in BG level after breakfast increase pre-breakfast short or rapid-acting insulin
Elevated BG level before evening meal increase pre-breakfast intermediate-acting insulin or increase dose pre-lunch of short or rapid-acting insulin if on basal-bolus regimen
Rise in BG level after evening meal increase pre-evening meal short or rapid-acting insulin

In addition

Unexplained hypoglycemia requires re-evaluation of insulin therapy
Hyper- or hypoglycemia occurring in the presence of intercurrent illness requires a knowledge of ‘sick day management’
Day-to-day insulin adjustments may be necessary for variations in lifestyle routine especially exercise or dietary changes
Various levels of exercise require adjustment of diabetes management
Special advice may be helpful when there are changes of routine, travel, school outings, educational holidays or other activities which require adjustment of insulin doses

Development of skills in the independent adjustment of insulin doses varies greatly among young people and families. To facilitate these skills 24-h telephone access to personnel experienced in pediatric diabetes care should be available. This assists not only general diabetic management and safe insulin adjustment but also provides invaluable support during illness and other crises. In this way, admissions to hospital may be prevented

Frequently used regimens