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
Intensive insulin replacement should be started as soon as possible after diagnosis to maintain blood glucose levels as close to normal as possible. This prevents diabetic ketoacidosis and reduces the likelihood of chronic complications.[59][60] The American Diabetes Association (ADA) recommends a target HbA1c goal of <7% (<53 mmol/mol) without significant hypoglycemia for many nonpregnant people with diabetes.[1] The choice between continuous infusion with an insulin pump and a regimen of multiple daily injections (MDI) is based on patient interest and self-management skills, cost, and physician preference.[1][62]
It is reasonable to begin therapy with 2-4 insulin injections daily to cover basal insulin requirements and to cover mealtime insulin needs. A combination of long-acting insulin (insulin glargine, insulin detemir, or insulin degludec) or intermediate-acting insulin (insulin NPH/isophane) should be used for basal dosing, and rapid-acting insulin (insulin lispro, insulin aspart, or insulin glulisine) or short-acting insulin (regular/human insulin) for bolus dosing. Treatment with analog insulins may provide the benefit of increased flexibility of lifestyle and less hypoglycemia as compared with human insulins.[63] In fact, in patients who are at high risk of hypoglycemia, the Endocrine Society recommends using long-acting insulin analogs rather than insulin NPH for those on basal insulin therapy, and rapid-acting insulin analogs rather than short-acting human insulins for those on basal-bolus insulin.[64] Similarly, the ADA recommends that for most adults with type 1 diabetes, insulin analogs are preferred over injectable human insulins to minimize hypoglycemia risk.[1] However, insulin analogs are more expensive.[65][66]
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Biosimilars of analog insulin may be available in some countries at a lower cost, making them more affordable. Ultra-rapid acting insulin analogs are also available for a more favorable postprandial glycemic effect.
Inhaled insulin is available as a rapid-acting insulin and can be useful for people with an aversion to injection.[1] Inhaled insulin is contraindicated in individuals with chronic lung diseases (including asthma and COPD), and is not recommended in smokers or recent ex-smokers (within the past 6 months).[1] Measurement of forced expiratory volume is required prior to and after starting inhaled insulin therapy.[1]
Total daily dose requirements can be estimated based on weight, with typical doses ranging from 0.4 to 1 units/kg/day.[1] A starting dose of 0.5 units/kg/day is usually appropriate for metabolically stable adults.[1] Higher doses are required during pregnancy, puberty, and illness.[1] In general, one half of the total dose is given as basal insulin to control glucose levels overnight and between meals, and one half as bolus dosing to control glucose levels after meals.[1] The bolus dosing, known as prandial insulin, is divided and given before meals. Patients need to monitor their blood glucose levels with a glucose monitor or a continuous glucose monitoring (CGM) device.[1] The insulin doses can be adjusted every 2 to 3 days to maintain pre-meal and post-meal targets.
Basal insulin can be administered as a basal rate of rapid-acting insulin via an insulin pump, or as daily injections of a long-acting insulin.[1] Patients on an insulin pump will take prandial insulin as a bolus before each meal. For those on MDI, 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. However, for greater flexibility of carbohydrate content of meals, pre-meal insulin should be calculated based on the estimated amount of carbohydrate in the meal and the patient's individual insulin-to-carbohydrate ratio.[1] A simple beginning approach is to use one unit of mealtime insulin for every 15 g of carbohydrate in the meal. 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 nutritionist. Using a food diary and 2-hour postprandial blood glucose measurements, the insulin-to-carbohydrate ratio can be adjusted. Estimates of the fat and protein content of meals may be incorporated into prandial dosing for added benefit.[1]
Regular insulin is given about 30 minutes prior to the meal, while rapid-acting insulin can be injected 15 minutes before to shortly after a meal. In children with erratic eating habits, rapid-acting insulin can be given just after the meal.
The timing of basal insulin in the MDI regimens should be based on both physician and patient preference. It is important that the natural profile of insulin secretion in the body is replicated by the use of basal insulin. The following should be considered when deciding on dose: insulin NPH is typically given twice daily; insulin detemir is typically given twice daily; insulin degludec is long-acting and can be given once daily in the morning or evening or any other time of the day. For consistency, this should preferably be delivered at the same time every day. Insulin glargine is usually given once daily. It is important to take it at the same time each day, preferably at night. A morning dose may be preferable if a patient is anxious about night-time hypoglycemia or if patient preference means this will help improve adherence. However, clinical experience, supported by a small study, suggests that insulin glargine may not last for 24 hours in some patients with type 1 diabetes mellitus and may therefore need to be given twice daily for optimum basal coverage.[105] Some patients take insulin glargine once daily at night and cover the tail end of the 24-hour period with extra rapid-acting insulin in the evening.
The regimen should be individualized to obtain the best possible glycemic control.
Primary options
insulin glargine
or
insulin NPH
or
insulin detemir
or
insulin degludec
-- AND --
insulin regular
or
insulin lispro
or
insulin aspart
or
insulin glulisine
or
insulin inhaled
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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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