Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
basal-bolus insulin
Offer the patient, whether they are an adult or child, a multiple daily injection basal-bolus insulin regimen from diagnosis.[37][35] Do not offer adults newly diagnosed with type 1 diabetes twice-daily mixed, basal only, or bolus only insulin regimens.[37]
Using a combination of long-acting insulin (insulin detemir, degludec, or glargine) for basal dosing, and rapid-acting insulin (insulin lispro, aspart, or glulisine) for bolus dosing, multiple daily injections (MDI) regimens can be designed based on physician and patient preference and modified based on glucose monitoring data.
In the UK, the National Institute for Health and Care Excellence (NICE) recommends twice-daily insulin detemir as basal insulin therapy for adults.[37] NICE advises considering one of the following alternatives to twice-daily insulin detemir: an insulin regimen that the patient is established on and meeting their agreed treatment goals; once-daily insulin glargine if the patient cannot tolerate insulin detemir or has a strong preference for once-daily basal injections; once-daily insulin degludec if there is a particular concern about nocturnal hypoglycaemia; once-daily ultra-long-acting insulin (e.g., insulin degludec) if the patient needs help from a carer or healthcare professional to administer injections.[37] If the patient does not meet their treatment goals with these options, NICE recommends considering other basal insulin regimens, taking into account the patient’s preferences and comorbidities, risk of hypoglycaemia and diabetic ketoacidosis, and any concerns around adherence.[37]
NICE recommends analogue rapid-acting insulins as the first-line choice for bolus dosing.[37]
There is no consensus as to whether insulin analogues are superior to conventional insulins for glycaemic control or reductions in complications.[67][68]
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An initial total daily dose of insulin in adults can be 0.2 to 0.4 units/kg/day. In children, an initial daily dose will be 0.5 to 1.0 units/kg/day, and during puberty the requirements may increase to as much as 1.5 units/kg/day. Often, when first started on insulin, patients with type 1 diabetes will experience a honeymoon period, during which they may require fewer units each day. In general, one half of the total dose is given as basal insulin and one half as bolus dosing.[46] The bolus dosing is divided and given before meals. Basal dose timing varies according to individual patient requirements and the type of insulin used (e.g., insulin detemir is usually given once or twice daily depending on the patient's needs, insulin glargine and insulin degludec are usually given once daily at any time of the day, but preferably at the same time every day). Administration times may vary; check your local guidelines for more information. Patients need to self-monitor their blood glucose levels. In adults, the insulin doses can be adjusted every 2 to 3 days to maintain target blood glucose. Encourage children and young people who are having multiple daily insulin injections to adjust the insulin dose if appropriate after each blood glucose measurement.[35]
To maintain an HbA1c target of 48 mmol/mol (6.5%) or lower, advise adults with type 1 diabetes to aim for: on waking, a fasting plasma glucose level of 5-7 mmol/L (90-126 mg/dL); before meals at other times of day, a plasma glucose level of 4-7 mmol/L (72-126 mg/dL); after meals, a plasma glucose level of 5-9 mmol/L (90-162 mg/dL) at least 90 minutes after eating; at bedtime, a personalised plasma glucose level that takes into account the timing of their last meal and its related insulin dose, and is consistent with the recommended fasting level on waking.[37]
Children and young people aged under 18 years should aim for: on waking, a fasting plasma glucose level of 4-7 mmol/L (72-126 mg/dL); before meals at other times of day, a plasma glucose level of 4-7 mmol/L (72-126 mg/dL); after meals, a plasma glucose level of 5-9 mmol/L (90-162 mg/dL).[35]
If the patient drives, ensure they are aware of the relevant local advice on plasma glucose level. In the UK, the Driver and Vehicle Licensing Agency (DVLA) advises to aim for a level of at least 5 mmol/L (90 mg/dL) before driving.[49]
The simplest approach to covering mealtime insulin requirements is to suggest a range of doses, such as 4 units for a small meal, 6 units for a medium-sized meal, and 8 units for a larger meal. For greater flexibility of carbohydrate content of meals, pre-meal insulin can be calculated based on the estimated amount of carbohydrate in the meal and the patient's individual insulin-to-carbohydrate ratio.
In adults, a conservative starting approach is to use 1 unit of mealtime insulin for every 15 g of carbohydrate in the meal (bear in mind, however, that the insulin-to-carbohydrate ratio might vary according to local protocols). Patients can use the carbohydrate content per serving listed on food packaging to assess the number of grams in their anticipated meal, but carbohydrate counting is best learned with the help of a dietitian or via a structured diabetes education programme.[37] Using a food diary and 2-hour postprandial blood glucose measurements, the insulin-to-carbohydrate ratio can be adjusted.
Regimens should be individualised to obtain the best possible glycaemic control.
A correction dose may be incorporated into the insulin doses based on pre-meal glucose levels.
An insulin pump (continuous subcutaneous insulin infusion [CSII]) may be considered in some patients for whom MDI regimens are inappropriate or unsuccessful.
In the UK, NICE recommends an insulin pump as an option for children younger than 12 years for whom MDI therapy is impractical or inappropriate; these patients would be expected to have a trial of MDI therapy at some point between the ages of 12 and 18 years.[69]
NICE also recommends a pump as a treatment option for those aged 12 years and older whose attempts to achieve target HbA1c levels with an MDI regimen have resulted in disabling hypoglycaemia with a significant impact on quality of life; these patients should only continue using a pump if it results in a sustained fall in HbA1c levels and/or a reduction in the frequency of hypoglycaemia episodes.[69]
The insulin pump has a subcutaneous insulin infusion port which is changed every 3 days. The pump uses short-acting or rapid-acting insulin, and provides a basal rate of insulin and delivers mealtime bolus dosing. However, the patient (or a parent or carer) must still measure blood glucose frequently (in practice, 4-7 times each day) in order to adjust the pump to deliver the appropriate amount of insulin. Insulin pumps may reduce hypoglycaemia, especially when combined with continuous glucose monitoring (CGM) systems and threshold suspend features, and improve HbA1c, while providing greater flexibility.[54][70][71][72][73] Because of the monitoring and dose adjustment required, use of a pump requires a motivated patient skilled in diabetes self-management and with access to practitioners trained in pump therapy.[74][75] If the patient is a child, they will need strong family support in place.[74]
Insulin pumps with glucose sensors integrated into the same unit are called sensor-augmented insulin pumps. Functionality between sensor and pump has been integrated in one available device: a 'closed loop' system. The basal insulin delivery can be determined automatically based on sensor glucose levels. These integrated devices use a computerised control algorithm to create the hybrid closed loop insulin delivery system, which functions as an artificial pancreas.[40][76][77] In clinical trials, such systems have been shown to reduce the risk of nocturnal hypoglycaemia and to improve glucose control, including in children.[78][79][80] Some models come with smartphone apps that can be used to monitor glucose and insulin dosing. Use of sensors and sensor-augmented pumps is increasing.
Remind the patient to rotate injection sites within the same body region. The Medicines and Healthcare products Regulatory Agency (MHRA) advises this is to prevent or reduce the risk of developing cutaneous amyloidosis (insulin lipodystrophy) at the injection site which may lead to poor diabetes control caused by lack of insulin absorption due to the amyloid mass.[81]
Insulin should not be withdrawn from insulin pen devices or cartridges.[37] NHS England warns that the strength of insulin in pen devices can vary by multiples of 100 units/mL, whereas insulin syringes have graduations only suitable for calculating doses of standard 100 units/mL. If insulin extracted from a pen or cartridge is of a higher strength than intended, and that is not considered in determining the volume required, it can lead to a significant and potentially fatal overdose.[82]
Ensure the risk of medication errors with insulins is minimised by prescribing insulins by brand name.[37] There are a number of 'sound-a-like' insulins and, in some cases, multiple different strengths and formulations of each type of insulin.[83]
In addition, follow local guidance on minimising the risk of medication error with high strength, fixed combination, and biosimilar insulin products.[37] MHRA: High strength, fixed combination and biosimilar insulin products: minimising the risk of medication error Opens in new window
Primary options
insulin detemir
or
insulin glargine
or
insulin degludec
-- AND --
insulin lispro
or
insulin aspart
or
insulin glulisine
Choose a patient group to see our recommendations
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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