Managing Type 1 diabetes Flashcards
(23 cards)
Insulin and metabolism
The aim of insulin therapy is to replicate physiological insulin production in order to minimise significant variations in blood glucose and reduce the likelihood of complications. The degree to which this replication can be achieved will depend on the particular insulin regimen used, together with several important patient factors including empowerment and the willingness to self-manage, the acceptability of multiple daily injections and the fear of hypoglycaemia.
Insulin is the major hormone secreted by the pancreas. It acts as an anabolic hormone, that is, it increases energy stores during times of adequate nutrition, working in harmony with the catabolic hormones (adrenaline, corticosteroids, glucagon and growth hormone), which mobilise glucose when energy expenditure increases.
By facilitating certain enzymes and inhibiting others, insulin has wide-ranging effects on the metabolism of carbohydrates, lipids and proteins. Insulin enhances cellular uptake of glucose from the blood in many tissues, particularly skeletal muscle and adipose tissue, thereby reducing blood glucose levels. The synthesis of energy stores (glycogen in the liver and skeletal muscle and fat in the liver and adipose tissue) is facilitated and their breakdown is inhibited. Tissue growth and cell division are also promoted by enhanced nucleic acid synthesis, amino acid assimilation and protein synthesis
what happens during physiological insulin production
In non-diabetic subjects there is a biphasic insulin secretory response following ingestion of food (see Figure). Within one minute of blood glucose levels rising, pre-formed insulin is released from the pancreas into the blood. Should hyperglycaemia persist, further insulin synthesis is stimulated and there is a delayed second phase of secretion after 45 minutes. Thus, normally, the plasma insulin curve closely parallels the plasma glucose curve throughout the day, reflecting even small changes in nutrient supply or demand. There is also a continuous basal level of insulin secretion throughout the 24 hours, independent of food intake, which contributes to the regulation of metabolism and promotes glucose uptake into cells.
Three characteristics of insulin
- Onset is the length of time before insulin reaches the bloodstream and begins lowering blood glucose
- Peaktime is the time during which insulin is at maximum strength in terms of lowering blood glucose
Duration is how insulin continues to lower blood glucose
- Peaktime is the time during which insulin is at maximum strength in terms of lowering blood glucose
Types of insulin regimens
- Twice daily fixed mixture
- Basal bolus regimen
- Continuous s/c insulin infusion
Insulin and oral agents in combination
Insulin regimen preference
A Basal-Bolus insulin regimen, (also referred to multiple daily injection therapy), is the preferred method of administering insulin to people with type 1 diabetes. Another approach, called a biphasic insulin regimen (sometimes referred to as a twice daily insulin regimen) is currently rarely ever used. Information about both approaches to insulin therapy is provided in subsequent pages for completeness.
NICE recommendations on insulin regimens
NICE now recommends only offering multiple daily injections (i.e. Basal–Bolus insulin regimens) as the insulin injection regimen of choice for all adults with type 1 diabetes and NOT to offer the twice-daily mixed insulin (Biphasic) regimens. 3 Furthermore, newly diagnosed patients with type 1 diabetes should not be offered any non-basal–bolus insulin regimens (that is basal only or bolus only). In practice, twice daily insulin regimens should only normally be reserved for rare situations when a multiple daily injection basal–bolus insulin regimen is not possible e.g. insituations where a patient cannot manage their own treatment independently or appropriately
What is a basal bolus regimen and what are its advantages
A basal-bolus regimen (Multiple daily injection therapy), involves the administration of one or more separate injections of a long acting or intermediate acting insulin together with separate injections of short or rapid acting insulin at or before each meal. The intermediate- or long-acting injection is given at the same time each day, commonly at bedtime. NICE recommends that insulin detemir (used twice daily) is used as the first-line choice for the basal component for type 1 diabetes3,5.
The advantage of a basal-bolus regimen is that it allows more flexibility over when meals are taken and also enables doses to be varied in response to different carbohydrate quantities in meals. 18 Multiple daily injection regimens also provide tighter glycaemic control, which is associated with reduced rates of diabetic complications compared with twice daily regimens6.
What is a biphasic regimen
A twice-daily insulin regimen is described as being biphasic because it involves two phases of activity. At each injection, a patient administers a mix of insulin containing a short acting and intermediate acting insulin. The insulin needs to be either manually mixed via syringe or, more typically administered as pre-mixed insulin via a cartridge or pre-refilled pen device. If a twice-daily regimen is required, it is important that patients keep to a consistent daily routine, 18
In practice, Biphasic or twice-daily insulin regimens are rarely used and are normally only reserved for situations when multiple daily injection basal–bolus insulin regimen is not possible or in situations where a patient experiences hypoglycaemia that affects their quality of life. 3
A twice-daily insulin regimen works on the assumption that the patient will have 3 meals each day hence it may be suitable for patients who have regular, consistent daily routines that include three main meals at similar times each day. It may also be appropriate for school children who cannot manage insulin administration appropriately as injections can be given before and after school without the need for a lunchtime injection 7.
By convention the number incorporated into the brand name refers to the percentage of short-acting insulin present. Generally biphasic insulin is injected 15 to 30 minutes before breakfast and the evening meal. There is individual patient variability with absorption and hence insulin mixes are suitable for some, but not all, patients. It is important to ensure that the insulin components are thoroughly mixed by inverting the pen device approximately 5 to 10 times before injection.
What is a bolus dose
The bolus dose of a Basal-Bolus insulin regimen (sometimes referred to as the insulin meal-time component) is insulin that is specifically taken at meal times to keep blood glucose levels under control following a meal. Bolus insulin needs to act quickly and so short acting insulin or rapid acting insulin are used19.
NICE recommends offering rapid‑acting insulin analogues that are injected before meals, rather then rapid‑acting soluble human or animal insulins, for mealtime insulin replacement for adults with type 1 diabetes. NICE also recommends not to advise on the routine use of rapid‑acting insulin analogues after meals for adults with type 1 diabetes. 3
A systematic review 9 comparing trials of rapid-acting insulin analogues with soluble insulin in patients with type 1 diabetes found significant reductions in HbA1c in favour of rapid-acting insulin analogues (lispro vs soluble insulin: aspart vs soluble insulin). This systematic review also reported that there was evidence that rapid-acting insulin analogues may reduce the frequency of nocturnal hypoglycaemia compared to soluble insulin
what is a basal dose
The basal dose of a basal-bolus insulin regimen (sometimes referred to as the insulin basal component or background insulin) provides a constant level of insulin sufficient to meet the background metabolic requirements without causing nocturnal hypoglycaemia. NICE recommends that insulin detemir (administered twice daily) should be the first-line choice for the basal component in the treatment of type 1 diabetes. 3 5
NICE further states that for adults with type 1 diabetes, one of the following basal insulins may be offered as an alternative to treatment with basal insulin detemir if3:
* an insulin regimen that is already being used by the person if it is meeting their agreed treatment goals (such as meeting their HbA1c targets or time in target glucose range and minimising hypoglycaemia)
* once-daily insulin glargine (100 units/ml) if insulin detemir is not tolerated or the person has a strong preference for once daily basal injections
* once-daily insulin degludec (100 units/ml) if there is a particular concern about nocturnal hypoglycaemia
* once-daily ultra-long-acting insulin such as degludec (100 units/ml) for people who need help from a carer or healthcare professional to administer injections.
Other basal insulin regimens for adults with type 1 diabetes should be considered only if the above regimens do not meet the agreed treatment goals. When choosing an alternative insulin regimen, the following should be taken into account:
* the person’s preferences
* comorbidities
* risk of hypoglycaemia and diabetic ketoacidosis
* any concerns around adherence
acquisition cost
High strength basal insulins
Several new insulin products have come to market recently, these include: two high strength long acting insulins which have concentrations greater than 100 units/mL (Tresiba®▼and Toujeo®) and a biosimilar of insulin glargine (Abasaglar®▼) 10
Healthcare professionals and patients need to understand the strength of insulin in these products and how to use them correctly to minimise the risk of medication errors, such as the wrong insulin dose being administered.
High strength insulin products have been developed for patients with large daily insulin requirements to reduce the number and volume of injections.
Abasaglar® is a biosimilar medicine based on insulin glargine 100 units/mL (Lantus®) and is licensed for the treatment of diabetes in adults, adolescents, and children aged 2 years and above. Abasaglar® has been shown to be equivalent to Lantus® in its pharmacokinetic and pharmacodynamic properties. However, as with other biosimilar medicines, some dose adjustment may be needed for some patients
Insulin:Carbohydrate ratio
This estimates the amount of insulin required to offset a 10g portion of carbohydrate. 10g of carbohydrate is commonly referred to as a carbohydrate portion (CP). Most people generally start using 1 unit of rapid-acting insulin for every CP. The ratio can be adjusted by 0.5 unit increments using pre-meal and 2 hour post-prandial glucose levels as a guide.
Eventually individuals may use different ratios for different meals due to changes in insulin sensitivity that occur during the day. Typical ratios vary from 0.5 to 4 units/10g carbohydrate.
syringes
Disposable insulin syringes (i.e. syringes that are specifically designed for insulin withdrawal) are available in 0.3ml, 0.5ml and 1ml volumes and are graduated in 100 units per ml. Administering insulin via a disposable syringe used to be common practice though this was before the introduction of insulin cartridge type devices (i.e. reusable pens) or prefilled pen devices. For this reason, insulin syringes are no longer commonly used.
(Note that if this method of insulin delivery is used by a patient, it is important to remind them not to use syringes that are not specifically designed for insulin administration. This is due to a risk of fatal overdose from insulin, if non-insulin syringes are used. Additionally, insulin syringes must never be used to withdraw insulin from an insulin cartridge or pre-filled pen as this could damage the pen device and lead to subsequent inaccurate dosing of insulin from the pen device
reusable pen devices
Reuseable pens are used in conjunction with 3ml insulin cartridges and pen needles. Pen devices are discrete and attract less attention when used in public compared with syringes. They are ideal for the visually impaired as many of the devices click audibly as each unit is dialed up. Reusable pens must only be used with compatible insulin cartridges
Disposable pen devices
Disposable pen devices are similar to the reuseable pens but are more convenient for those patients who experience difficulties when changing insulin cartridges. These pens should be disposed of appropriately once the insulin is finished. A wide range of disposable pens are available for use with different types of insulins.
Needles
The aim is to inject insulin into the subcutaneous fat of the skin. Injecting insulin into the outer skin may significantly reduce absorption, whilst injecting deeply into muscle or possibly the venous circulation could cause rapid effects increasing the risk of hypoglycaemia.
Offer needles of different lengths to adults with type 1 diabetes who are having problems such as pain, local skin reactions and injection site leakages3.
All needles for use with pen devices are single use only and it is very important to encourage patients to adhere to this practice.
Insulin injection sites
Insulin injections are given subcutaneously usually in the abdomen (fastest absorption), arm (intermediate absorption) or thigh/buttocks (slowest absorption). Patients should be directed to inject at a 90 degree angle to the skin. The skin should be lightly pinched up with 2-3 fingers to reduce the risk of an inadvertent intramuscular or intraperitoneal injection. The injection should remain in the skin for at least 7 seconds to ensure complete release of the dose. As the injection site may alter the rate of absorption of insulin (e.g. exercising the underlying muscles may significantly increase absorption rates in the thigh), patients tend to inject longer-acting insulins into the thigh and shorter or rapid-acting insulins into the abdomen. In an emergency situation insulin may be given intravenously, although this should only be done under strict medical supervision
Sharps disposal
All patients should dispose of sharps associated with their diabetes treatment appropriately. Sharps bins are available on prescription and are accepted by the vast majority of pharmacies. Encourage patients not to overfill their bin and seal it before bringing it to the pharmacy. These bins are then collected as part of pharmaceutical waste collection schemes by registered contractors.
site complications
Repeated injections into the same specific area within a subcutaneous site may, in the longer term, lead to a build up of fatty lumps known as lipohypertrophy (see Picture). This may lead to erratic absorption of insulin from the site. Lipohypertrophy can be avoided by routine rotation of the injection site within a given anatomical area. Local allergic reactions can occasionally occur at the site of insulin injection and are characterised by itching and erythema. In most cases the allergy is due to one of the constituents of the insulin preparation rather than from the insulin itself, which is highly purified.
Driving
It is important that a patient’s ability to recognise “hypos” should be checked regularly as patients tend to become less sensitive to the warning signs as time progresses. Repeated hypoglycaemia, especially unrecognised nocturnal hypoglycaemia, is a major cause of an individual losing their hypoglycaemic awareness.
The DVLA has issued guidance about the precautions that drivers with insulin treated diabetes should take when driving or planning to drive including advice about how to manage episodes of hypoglycaemia or developing hypoglycaemia whilst driving.
Alcohol
The recommended limits for alcohol intake are the same for people with diabetes as for the rest of the population, i.e. no more than 2 units daily for men or women 17 though individuals with diabetes need to be careful about how much alcohol they consume. They need to be aware about how alcohol can affect diabetes and how to manage when drinking alcohol and therefore should be advised to talk to their specialist diabetes team for advice on drinking alcohol safely. 25
Alcohol can increase the risk of developing hypoglycaemia with the risk being proportional to the amount of alcohol consumed. Hypoglycaemia may occur for up to 16 hours after large quantities of alcohol are consumed. Many who use insulin may need to reduce their morning dose after significant alcohol intake the night before.
General advice for people with diabetes include:
* don’t drink on an empty stomach; if drinking throughout the evening, snack on some form of carbohydrate, e.g. crisps
* if drinking larger quantities of alcohol, always take some carbohydrate before going to bed
wear some form of diabetes identification and inform a friend of your condition as the ability to recognise and treat hypoglycaemia is reduced when drinking larger quantities of alcohol.
Exercise
The variables that influence glucose during exercise are:
* the timing, duration and intensity of the exercise
* competition stress, external temperature and hydration
* the amount of high GI carbohydrate consumed
* insulin dose with preceding meal and basal requirements
* recent hypoglycaemia.
Patients with type 1 diabetes must measure blood sugars before, during and for several hours after exercise to interpret the effect of exercise on blood glucose. General recommendations are:
* Different sports have different effects on blood sugar so patients are advised to test their blood glucose levels around exercise regularly to learn how different sports and session lengths affect their blood sugar levels
* if sugars are > 12 mmol/L without ketones, delay replacing carbohydrate during exercise until sugars have fallen
* if sugars are < 7 mmol/L pre-exercise, consider taking high GI carbohydrate at the start of exercise
* avoid exercise if ketones are present
* ideally exercise 1 to 2 hours after a meal
consider reducing the next dose of mealtime insulin.
Insulin Passport
The Insulin passport was first developed by the NHS to improve patient safety by alerting healthcare professionals to the correct insulin that a patient should be receiving, to empower patients to take an active role with their insulin treatment, and to assist with the safe administration of insulin in emergencies.
The original version of the insulin passport, which still is used by various health trusts, consists of a single, double-sided sheet that folds up to credit-card size containing the following information:
* up-to-date details of the type of insulin, syringes and pens used by a patient
* emergency information that tells others what to do if the patient is found ill or unconscious
* information to help in an emergency, including contact names and telephone numbers and other medication that that the patient could be taking
* optional facility for patients to record their other medication.
Some health trusts use a credit card sized version made out of of plastic or card material which is colour coded to match the patient’s specific insulin treatments. These cards typically contain images of the insulin box container, the insulin pen device and the manufacturers specific branding with a small space available for written patient details. This type of insulin passport provides a helpful visual reference to promote rapid identification of the correct insulin type and brand during prescription assembly and subsequent supply to the patient including alerting healthcare professionals during emergencies.
