Multiple daily injection (basal-bolus) insulin regimen for hospitalised adults with hyperglycaemia

Insulin treatment using a multiple daily injection (basal–bolus) insulin regimen should be started in all noncritically ill–hospitalised adults with hyperglycaemia (blood glucose concentration more than 10 mmol/L).

A multiple daily injection (basal–bolus) insulin regimen is preferred because use of fixed-dose combination (biphasic premixed) insulin is associated with an increased incidence of hypoglycaemia in hospitalised adults.

Note: Always follow local hospital protocols for hyperglycaemia and insulin management.
Follow local hospital protocols if available. There are many different approaches to management of hyperglycaemia and insulin in hospitalised adults. If a local protocol is not available, an example of starting a multiple daily injection (basal–bolus) insulin regimen is given in Example of starting a multiple daily injection (basal-bolus) insulin regimen in hospitalised adults.

For a multiple daily injection (basal–bolus) insulin regimen, long-acting basal insulin is given once or twice daily at the same time each day. Capillary (finger-prick) blood glucose concentrations should be measured before meals. Rapid-acting bolus insulin is given before meals (preprandial) and includes a supplemental (correction) dose of rapid-acting bolus insulin if there is hyperglycaemia before a meal. For insulin formulations, see Action profiles of insulin formulations.

In an adult with poor or variable oral food intake, rapid-acting bolus insulin may be given immediately after a meal when they have eaten and tolerated the food.

Rapid-acting bolus insulin should not be withheld if the adult has hypoglycaemia before a meal but is going to eat, especially if they have type 1 diabetes. The hypoglycaemia should be treated and rapid-acting bolus insulin given as usual with the subsequent meal (see Hypoglycaemia in patients with diabetes). Withholding the bolus insulin at mealtime will result in hyperglycaemia.

Blood glucose concentrations must be measured regularly to guide insulin doses. Consider measurement of blood ketone concentration in hospitalised adults who are acutely unwell, especially if they have type 1 diabetes (see Insulin treatment for hospitalised adults with type 1 diabetes) or they have been taking a sodium-glucose co-transporter 2 (SGLT2) inhibitor (see Considerations for use of noninsulin antihyperglycaemic drugs in hospitalised adults for considerations for use with an SGLT2 inhibitor).
Table 1. Example of starting a multiple daily injection (basal-bolus) insulin regimen in hospitalised adults

[NB1]

patients already using insulin

patients not already using insulin:

adjusting insulin dosage

Patients already using insulin

The total usual daily insulin dose (sum of all doses of insulin given daily, irrespective of formulation) should be divided in a 50:50 ratio between:

  • basal dose—long-acting insulin given subcutaneously once daily at the same time each day
  • bolus doses—rapid-acting insulin given subcutaneously in divided doses before meals.

Patients not already using insulin

As a starting dose, give:

  • basal dose—long-acting insulin 0.2 units/kg (up to 30 units) subcutaneously, once daily at the same time each day
  • bolus doses—rapid-acting insulin 0.2 units/kg (up to 30 units) subcutaneously, daily in divided doses before meals [NB2].

Example of calculating a starting insulin dose [NB3]:

For a 90 kg hospitalised patient with hyperglycaemia who is eating regular meals, give:

  • basal dose: 0.2 × 90 = 18 units of long-acting insulin
  • total bolus dose: 0.2 × 90 = 18 units of rapid-acting insulin. Give one-third (6 units) of the total rapid-acting insulin dose before each meal.

Supplemental (correction) bolus doses of rapid-acting insulin can be added to the bolus insulin dose given before the meal if a patient is hyperglycaemic.

Example of supplemental doses:

Supplemental doses depend on the BGC before the meal, one example is [NB4]:

  • BGC 8.1 to 12 mmol/L—add an extra 1 unit rapid-acting insulin
  • BGC 12.1 to 16 mmol/L—add an extra 3 units rapid-acting insulin
  • BGC 16.1 to 20 mmol/L—add an extra 4 units rapid-acting insulin
  • BGC more than 20 mmol/L—add an extra 6 units rapid-acting insulin.

Adjusting insulin dosage

Review insulin dosage daily and adjust based on the BGCs measured in the previous 24 to 48 hours.

Insulin dose adjustments of 10 to 20% should be made pre-emptively to avoid future episodes of hypoglycaemia or hyperglycaemia, targeting the likely insulin dose involved (basal or bolus).

Consider any changes in the patient’s clinical state that may affect their insulin requirement, such as resolving infection, increasing oral intake or increasing mobility.

Note:

BGC = blood glucose concentration

NB1: Follow a local protocol if available.

NB2: Rapid-acting insulin is generally preferred to short-acting insulin as the bolus component. It reduces the postprandial rise in blood glucose concentration and reduces the risk of overnight hypoglycaemia compared with short-acting insulin.

NB3: This is only a guide—insulin must be prescribed in whole units; round doses up or down.

NB4: Patients using higher doses of insulin (more than 50 units daily) or who weigh more than 75 kg may need higher supplemental doses of insulin. Similarly, those who are using less than 25 units of insulin daily or weigh less than 50 kg may need less supplemental insulin—seek specialist advice.