Insulin regimes in Type 2 diabetes

According to NICE recommendations, NPH (isophane) insulin or a long-acting analogue should be used when initiating insulin in type 2 diabetes patients (1).

In majority of patients there is suboptimal glycaemic control even with initial insulin regiments.

• HbA1C was 7.5% or higher in 74% of patients 6 months after starting insulin therapy
• HbA1C was below 6.5% in only 24% or fewer after 1 year (1).

NICE recommends that in patients whom target HbA1C with the initial regimen is not reached without problematic hypoglycaemia and:

• if on basal regimen should consider additional meal-time doses or switching to a premixed insulin
• if on premixed insulin once or twice daily, it suggests they should consider an additional meal-time injection or change to a basal regimen plus meal-time injections (1).

Some proposed insulin regimes for patients with Type 2 diabetes (2):

• Once Daily - Intermediate regimen This may be used to supplement the daytime oral hypoglycaemic medication. Use intermediate acting insulin, which provides a low background level of insulin. Daily insulin requirements = 0.5 units / kg body weight approximately e.g. 0.5 x 72kg = 36 units Of which 50% will be basal requirement 36 x 50% = 18 units Take 60% of this daily dose for 'safety' 18 x 60% = 11 units
  • rounded up to 12 units for ease of administration 12
  • a safe starting dose would be e.g. 12 units of intermediate acting insulin, usually given at bedtime
    
    
• Twice Daily Regimen

For twice daily regimens the most frequently used option is a premixed fixed combination of short and intermediate acting insulin or a rapid acting insulin lispro or aspart mix. A twice-daily intermediate acting insulin is an alternative choice and may be appropriate in the elderly where there is a concern regarding the risk of hypoglycaemia.

Daily insulin requirements = 0.5 units / kg body weight approximately e.g. 0.5 x 72kg = 36 units

Take e.g. 60% 'for safety' 36 units x 60% = 22 units

Split the dose 50%: 50% before breakfast and evening meal. i.e. 11 units bd. Rounded up to 12 units for ease of administration.

Generally the final insulin dose required will be nearer to 60%/40% divide.

• Basal Bolus Regimen

This is the most intensive regime with three pre-prandial doses of short /rapid acting insulin and a bedtime dose of intermediate or long acting insulin. While this regime offers no improvement in metabolic control compared to any other insulin regime, this may be the most suitable regimen for people who do not have a stable daily routine as the time and dose of insulin can be varied according to when the meal is taken and its carbohydrate content.

Generally 30 - 50% of the total daily insulin requirements should be given as intermediate or long acting insulin at bedtime with the remaining insulin being given as short / rapid acting before breakfast, lunch and evening meal depending on the needs of the individual.

Daily Insulin requirements = 0.5 units / kg body weight approximately e.g. 0.5 x 72kg = 36 units

Take e.g. 60% 'for safety' 36 units x 60% = 22 units

When commencing a basal bolus regimen where three pre-prandial doses of short/rapid acting insulin are to be taken prior to breakfast, lunch and evening meal and intermediate acting/ long acting analogue insulin at bedtime the total daily dose may be calculated as follows;

22 units as above. -50% of the total daily dose is basal = 11 units e.g. 'rounding down' for ease of administration = 10 units

Daily bolus insulin dose therefore is 22 -10 (basal dose) = 12 units of short acting insulin.

This is divided into 3 for pre breakfast, lunch and evening meal = 4 units each meal. 10 units of intermediate/long acting analogue are given prior to bed.

The insulin can then be increased to the requirement of the individual.

In general, it is beneficial to commence the individual with Type 2 diabetes on a twice-daily insulin regimen initially until they feel comfortable with injections (2).

In consideration as to whether to initiate once or twice daily insulin in type 2 diabetic patients:

• there is study evidence that (3) in subjects with type 2 diabetes poorly controlled on oral hypoglycaemic agents, initiating insulin therapy with twice-daily biphasic insulin aspart 70/30 (prebreakfast and presupper) was more effective in achieving HbA(1c) targets than once-daily glargine, especially in subjects with HbA(1c) >8.5%

Notes (4):

• in consideration of starting dose of insulin - if using analogue rather than human insulin then use a 10% dose reduction as a precaution

Reference:

1. Barnett A et al. Insulin for type 2 diabetes: choosing a second-line insulin regimen. Int J Clin Pract. 2008;62(11):1647-53
2. NHS (Greater Glasgow and Clyde). Guidelines for Insulin Initiation and Adjustment in Primary Care in patients with Type 2 Diabetes: for the guidance of Diabetes Specialist Nurses (accessed 14/2/16)
3. Raskin P et al. Initiating insulin therapy in type 2 diabetes: a comparison of biphasic and basal insulin analogs. Diabetes Care 2005;28:260-5n
4. Novo Nordisk (August 2005). Human to Analogue Transfer Guide.