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PirjoIlanne-Parikka

Type 1 Diabetes: Treatment

Essentials

  • Insufficient or absent insulin production by the pancreatic beta cells can be compensated by administration of insulin preparations into the subcutaneous fat by injection or with an insulin pump.
  • The aim is to keep blood glucose levels as close to normal as possible, without creating disturbing or severe hypoglycaemias or wide daily fluctuations of glucose levels.
  • Patients can adjust the insulin dosage themselves based on self-monitoring of blood glucose and/or continuous glucose monitoring.
  • If target glucose values are not achieved with an appropriate multiple injection regimen, adequate guidance and continuous glucose monitoring, the suitability of insulin pump therapy should be considered together with the patient.
  • Blood pressure and blood lipids must also be well controlled.

Aims of treatment Glycaemic Control for Slowing the Progression of Microvascular Complications in Diabetes Mellitus, Different Intensities of Glycaemic Control for Pregnant Women with Pre-Existing Diabetes

  • The primary aims of treatment of type 1 diabetes include:
    • smooth everyday life and good functional and working ability
    • for the person with diabetes to learn to be an expert in his/her disease and self care
    • prevention and slowing down of diabetic organ changes and complicating diseases
    • optimum quality and length of life.

Blood glucose

  • The general targets for blood glucose levels in self-monitoring are 4-7 mmol/l in the morning and before meals and below 10 mmol/l after meals.
    • If the person is highly susceptible to hypoglycaemia or of an advanced age, 5-8 mmol/l can be a suitable before-meal target.
    • Despite careful treatment, blood glucose concentrations fluctuate.
      • The need for insulin varies at different times of day, on different days and periodically.
      • The absorption and effects of different insulin products differ.
      • The composition and absorption of food, and gastric emptying vary.
      • Stress and physical exercise may raise or lower blood glucose levels.
      • In women, the menstrual cycle affects insulin requirements.
  • The general target for glycohaemoglobin (HbA1c) is less than 53 mmol/mol (7%), without episodes of severe hypoglycaemia.
    • On individual grounds, the target may be stricter, below 48 mmol/mol (e.g. recently diagnosed diabetes, effective utilization of continuous glucose monitoring, pump therapy, pregnancy), or less strict, below 58 mmol/mol (e.g. proneness to hypoglycaemia, therapeutic challenges, short life expectancy).
  • The general aim of continuous glucose monitoring is that more than 70% of readings are between 3.9 and 10 mmol/l (TiR, Time in Range).

Blood pressure and lipids

  • In people with diabetes, hypertension and disorders of lipid metabolism have the same background of genetic and lifestyle factors and overweight as in those without diabetes.
  • Type 1 diabetes as such does not raise blood pressure in the absence of kidney disease.
  • In people with type 1 diabetes, hypertension increases the risk of not only cardiovascular disease but also diabetic kidney and retinal disease.
  • Insulin treatment increases the amount of HDL cholesterol. However, its protective effect is not too good.
  • For general aims, see Table T1.
  • Find out about local policies concerning reimbursement of medication for hypertension and disorders of lipid metabolism.

General aims of treatment of type 1 diabetes

VariableGeneral aims adjusted individually based on characteristics such as advanced age, proneness to hypoglycaemia or pregnancy
HbA1c<53 mmol/mol (7%)
Blood glucose in self-monitoring4-7 mmol/l before meals and at night
mostly < 10 mmol/l after meals
Continuous glucose monitoringTime in the 3.9-10.0 mmol/l range: > 70%
Time in hyperglycaemia, > 10.0 mmol/l: < 25%
Time in hypoglycaemia, < 3.9 mmol/l: < 5%
Mean glucose value: < 8.6 mmol/l
Glucose variability, %CV: ≤ 36%
Glucose Management Indicator, GMI: < 53 mmol/mol
P-Chol-LDL<2.6 mmol/l - patients with moderate risk:
  • young people (< 35 yrs) without risk factors (smoking, hypertension, dyslipidaemia, obesity, family history) and duration of T1D < 10 yrs
<1.8 mmol/l - patients with high risk:
  • T1D > 10 yrs without target organ damage
  • T1D and even just one risk factor (smoking, hypertension, dyslipidaemia, obesity, family history)
<1.4 mmol/l - patients with particularly high risk:
  • coronary artery disease or other atherosclerotic arterial disease
  • T1D and target organ damage (albuminuria, renal failure, retinopathy)
  • T1D and 3 risk factors (smoking, hypertension, dyslipidaemia, obesity, insulin resistance, etc.)
  • T1D > 20 yrs
Blood pressure<140/80 mmHg (< 135/80 mmHg measured at home)
<130/80 mmHg (< 125/80 mmHg measured at home) in patients with diabetic kidney disease, and possibility of reaching the target without adverse effects
WeightNormal (BMI < 25)
LifestyleDaily activity and regular physical activity
Dietary choices promoting cardiac health and glucose control
Sufficient rest and sleep
No smoking
No more than moderate alcohol consumption

Insulin products in the treatment of type 1 diabetes

Long-acting insulin derivatives

  • Insulin degludec, 100 units/ml and 200 units/ml, insulin detemir and glargine, 100 units/ml and 300 units/ml, are long-acting insulin derivatives.
  • Long-acting insulin is injected into a wide area on the thigh or buttock.
    • It can also be injected into the side of the abdomen / flank if there is too little fatty tissue in the thighs.
  • The effect of insulin detemir begins within 1-2 h and continues usually for 12-24 h, depending on the dose.
    • The effect is relatively even; in some people, there may be a slight peak of effect at 6-8 hours from injection.
    • People with type 1 diabetes usually inject insulin detemir twice daily, in the morning/midmorning and in the evening.
    • The times of injection should not vary by more than ± 2 h from day to day.
  • The effect of insulin glargine, 100 units/ml, begins within 2-4 h and usually lasts for 20-24 or as long as 26 h.
    • The effect is relatively even; there may be a slight peak in some people.
    • People with type 1 diabetes inject insulin glargine, 100 units/ml, usually in the evening, thus ensuring that insulin levels remain sufficient until the next morning.
    • For some people, it is more suitable to divide the dose into two daily injections, better ensuring more stable levels throughout 24 h.
    • The times of injection should not vary by more than ± 3 h from day to day.
  • The effect of insulin glargine, 300 units/ml, begins within 2-4 h and usually lasts for 24-36 h.
    • The effect is even; there is usually no peak of effect.
    • The risk of hypoglycaemia is lower than with insulin detemir or glargine, 100 units/ml.
    • The product is injected once daily.
    • Injections can usually be given at any time of the day.
  • The effect of insulin degludec, 100 units/ml and 200 units/ml, begins within 3-4 h and lasts for more than one day, i.e. 33-42 h.
    • The effect is even and predictable, i.e. insulin is very similarly absorbed from day to day.
    • The risk of hypoglycaemia is lower than with insulin detemir or glargine, 100 units/ml.
    • The product is injected once daily.
    • The times of injection are flexible as long as there is a minimum of 8 h and a maximum of 40 h between injections.

Rapid-acting insulin derivatives

  • Insulin aspart, insulin glulis and insulin lispro are rapid-acting insulin products.
    • They all act very similarly, and most people can therefore use any rapid-acting insulin equally well.
    • The effect of rapid-acting insulins begins in 10-20 minutes. The peak effect is achieved at 1-2 hours, and the effect continues for 2-5 hours, depending on individual characteristics and the dose.
    • Nevertheless, there may be individual differences in the effects of various products.
      • If a suboptimal effect is suspected, another rapid-acting insulin product can be tried.
    • A slightly faster acting insulin aspart has been developed.
      • Its effect begins about 5 minutes faster than that of other rapid-acting insulins.
      • It works better than other rapid-acting insulins in some people but not all.
    • Rapid-acting insulin is usually injected over a wide area on the abdomen.

Principles of insulin administration

Insulin requirement

  • The total daily insulin requirement of a normal-weight adult with type 1 diabetes is usually 0.4-1.0 units/kg.
    • If the person has some residual endogenous insulin secretion or is very sensitive to insulin, the requirement may be less.
    • The insulin requirement is increased by obesity, stress, sickness, puberty and pregnancy. In women, the menstrual cycle also often affects insulin requirements.
    • The need for insulin varies at different times of the day, on different days and periodically.
    • In adults, insulin requirements are usually higher about 4 hours before and after awakening.
      • This is called the dawn phenomenon and the get-up phenomenon.
  • If the total daily insulin dose (basal insulin + mealtime insulin + corrective insulin) exceeds 1 unit/kg, try to find the reason for the higher insulin requirement.
    • Are the injection sites too close together, is there induration or oedema or are there injection site reactions affecting the absorption of insulin?
    • Is there some inflammation or stress increasing the need for insulin?
    • Doesn't the insulin product work?

Basal insulin in a multiple injection regimen Intermediate Acting Versus (Ultra-)Long Acting Insulin for Type 1 Diabetes Mellitus

  • In adults on an ordinary diet, usually slightly less than half (40-50%) of the total daily insulin, or about 0.2-0.5 units/kg, should be derived from basal insulin.
  • In practice, in outpatient treatment of slowly developed insulin deficiency, for instance, basal insulin administration can be started at 8-12 units/day, and the dose can subsequently be increased by about 10% at a time once or twice a week according to continuous glucose monitoring or blood glucose tests.
  • Basal insulin should be given in the lowest number of units to keep blood glucose levels even during the night on continuous glucose monitoring or to keep the blood glucose difference in paired evening/morning blood glucose tests no more than ± 3 mmol/l and prevent the glucose level from rising or falling too much during the daytime if the interval between meals is prolonged.
    • The dose is also correct if glucose levels are at the target level of 4-7 mmol/l in the morning after waking up, before meals and during the night.
    • An amount of basal insulin that exceeds the requirement can easily lead to recurring hypoglycaemias particularly at night, to a need for snacks and to weight gain.
  • In a patient with insulin deficiency, the administration of basal insulin must not be discontinued in any circumstances although it may be necessary to reduce the dose in certain situations, such as if the patient has a gastroenteritis.
  • The blood glucose lowering effects of one unit of different basal insulin products are not necessarily the same.
    • When changing basal insulin products, the dosage must be adjusted based on continuous glucose monitoring or self-monitoring.
    • When changing from a basal insulin administered twice daily to a product administered once daily, the dosage should be reduced by about 20% considering HbA1c.

Basal insulin in pump therapyContinuous Subcutaneous Insulin Infusion for Type 1 Diabetes

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  • In pump therapy, the effect of basal insulin is achieved by continuous infusion of rapid-acting insulin into subcutaneous fatty tissue.
    • In most adults on an ordinary diet, the share of basal insulin administered with a pump is 30-40% of the total daily amount of insulin.
    • In adults, the normal basal rate is 0.5-1.5 units/h.
  • When changing from a multiple injection regimen to pump therapy, the insulin requirement decreases by about 10-30% depending on the HbA1c level.
    • For example, a dose of basal long-acting insulin of 24 units in a multiple injection regimen would correspond to 20 units in pump therapy. Divided into equal doses, this would correspond to about 0.8 units/h.
    • Based on continuous glucose monitoring, the administration rate can be set to correspond to the varying needs at different times of the day.
    • For example, at 00-03 a.m. 0.6 units/h; at 03-09 a.m. 1.0 units/h; at 09 a.m. to 09 p.m. 0.9 units/h; at 09-12 p.m. 0.6 units/h.
  • It is easy to increase or decrease the basal insulin dosage on the pump depending on the needs at any given time, in association with physical exercise or on sick days, for example.
  • An insulin sensor-augmented pump communicates wirelessly with a glucose sensor doing constant glucose monitoring. The sensor sounds an alarm if the glucose level falls out of the defined range. The sensor does not influence insulin administration unless it features a predictive low glucose suspend function stopping the delivery of basal insulin.
  • A hybrid pump administers basal insulin independently based on continuous glucose monitoring. It reduces the administration of basal insulin when blood glucose levels fall and increases it when blood glucose levels rise.

Mealtime insulin doses

  • For the administration of mealtime insulin, insulin-carbohydrate ratios must be defined for various times of the day.
    • The insulin-carbohydrate ratio is the amount of rapid-acting insulin required to cover a carbohydrate dose of about 10 g.
      • For pump therapy, the amount of carbohydrates covered by 1 unit of rapid-acting insulin is often calculated.
    • The insulin-carbohydrate ratio can be defined by paired pre- and post-meal blood glucose tests.
      • Blood glucose should be measured or checked using a glucose sensor before and about 2 h after a meal.
      • If the insulin-carbohydrate ratio and timing of injection are appropriate, blood glucose levels will not rise by more than 2-3 mmol/l from the preprandial level and will return to that level within about 4 h.
    • An approximate insulin-carbohydrate ratio can be obtained by dividing 500 by the total daily insulin dose.
      • In some people, 350 is a more appropriate number to be divided, particularly in association with breakfast.
      • If the total daily insulin dose is about 50 units, the insulin-carbohydrate ratio is 500/50 = 10, i.e., 1 unit of rapid-acting insulin will cover about 10 g of carbohydrates, or 10 g of carbohydrates will require 1 unit of rapid-acting insulin.
      • If the total daily insulin dose is about 30 units, the insulin-carbohydrate ratio is 500/30 = 16.6, i.e., 1 unit of rapid-acting insulin will cover about 17 g of carbohydrates, or 10 g of carbohydrates will require 0.6 units of rapid-acting insulin.
  • Rapid-acting insulin is given in association with meals and snacks according to the amount of carbohydrates eaten, the pre-meal blood glucose levels and any physical exercise taken before or after the meal.
    • If continuous glucose monitoring is used, the dose injected for a meal can be adjusted up or down depending on the direction of the trend arrow and the rate of change.
  • Food rich in protein or fat or both, such as a pizza, large steak, large portion of fatty fish or a fatty potato dish, may also affect the need for mealtime insulin.
    • If these are eaten, it may be necessary to administer slightly more rapid-acting insulin than would be necessary for carbohydrates, only, and to divide the dose into two.
    • The need for a further dose varies individually and must be defined by monitoring blood glucose levels.
  • The insulin-carbohydrate ratio and thus the need for mealtime insulin often varies at different times of the day.
    • In most normal-weight adults, the daytime insulin-carbohydrate ratio is 0.8-1.2 units / 10 g carbohydrates.
      • In insulin-sensitive people, the ratio may be 0.4-0.5 units / 10 g carbohydrates.
      • In insulin-resistant people, the ratio may be 2-3 units / 10 g carbohydrates.
    • Due to the morning insulin resistance, the requirement for breakfast may be 1.5-2 units / 10 g carbohydrates.
    • The requirement for an evening snack may be lower particularly after a day with a lot of physical activity.
  • If a multiple daily injections regime is begun in outpatient care, 0.5 units / 10 g carbohydrates can first be given, and the ratio specified further by continuous glucose monitoring or paired pre- and post-meal glucose tests at different times of the day.
  • The principle of administration of mealtime insulin does not differ essentially in insulin pump therapy from multiple daily injections.
    • An insulin pump dose calculator facilitates the dosing of mealtime insulin.
      • The individual target glucose level, estimated effective time of rapid-acting insulin, insulin-carbohydrate ratio and insulin sensitivity factors at various times of the day are set in the dose calculator.
      • The dose calculator suggests a suitable insulin dose based on the glucose sensor reading and the estimated amount of carbohydrates in the meal.
    • An insulin pump can be used to administer mealtime insulin at various rates.
      • With a normal bolus, the entire bolus is given at once.
      • When using a slow bolus, you can choose, depending on the meal, the time during which the bolus will be given.
      • For a combination bolus, the user him-/herself can adjust the share of the bolus given immediately and the time during which the rest of the bolus will be given.
  • Some hybrid pumps can also give small correction boluses.

Timing of mealtime insulin

  • Rapid-acting insulin should be injected before a meal, as far as possible, because otherwise blood glucose will rise before the insulin starts exerting its effect.
    • If blood glucose is at the target level before the meal, it is normally useful to inject rapid-acting insulin 15-20 minutes before starting to eat.
    • If blood glucose exceeds the target before the meal, it may be necessary to give an injection 20-30 minutes before eating or to first correct the blood glucose that is over the target by giving a correction dose of rapid-acting insulin calculated on the basis of the individual insulin sensitivity.
    • For a meal with a lot of protein or fat or both, it is possible to wait until starting to eat before injecting the rapid-acting insulin, and to possibly administer it in two doses.
    • Injection before a meal is particularly important at breakfast, when the insulin requirement is usually higher than at other times of the day.
    • During daytime, such as when eating out for lunch, it is often necessary to compromise and only inject rapid-acting insulin after compiling the meal.
    • If a person does not know in advance how much they are going to eat or in the case of a buffet-type meal, a dose covering 30 g carbohydrates, for instance, can be injected first and the rest later.
      • When using an insulin pump, it is easier to administer mealtime insulin in several doses, as necessary.

Corrective insulin dose

  • If blood glucose is transiently elevated before a meal and there will be no physical exercise following the meal, a small corrective dose of rapid-acting insulin should be injected in addition to what is injected to cover the carbohydrates in the meal.
  • The insulin sensitivity factor needs to be defined to be able to choose the dose of corrective insulin.
    • The insulin sensitivity factor shows how much one unit of rapid-acting insulin lowers the blood glucose level.
    • An approximate insulin sensitivity factor value can be obtained by dividing 100 by the total daily insulin dose.
      • If the total daily insulin dose is about 50 units, the insulin sensitivity factor is 100/50 = 2, i.e., 1 unit of rapid-acting insulin will lower blood glucose by about 2 mmol/l.
  • On days of sickness, insulin resistance and any ketosis increase the need for corrective insulin.
  • If blood glucose values are constantly elevated before a certain meal, the reason must be investigated more closely instead of repeatedly injecting corrective doses.
    • The reason may be that the mealtime insulin dose for the preceding meal was too low, leaving blood glucose elevated.
    • Or the reason may be insufficient effect of the basal insulin.
      • The basal insulin dose should not be increased until a glucose sensor or paired pre- and post-meal glucose tests have been used to find out whether the insulin-carbohydrate ratio for the preceding meal was appropriate.

Timing of corrective insulin

  • If blood glucose is not at the target level, corrective insulin should be injected before a planned meal, as necessary.
  • Corrective doses are also needed on days of sickness and sometimes in association with physical exercise that raises blood glucose levels.
  • Rapid correction between meals should be avoided or kept at a moderate level.
    • Not injecting mealtime insulin until during or after a meal is a common reason for postprandial blood glucose excursions.
      • The rapid-acting insulin does not take effect sufficiently soon, particularly if the meal includes rapidly absorbed carbohydrates.
      • However, blood glucose will return to the pre-meal level within about 4 h.
      • It is also common for delayed injection to cause first hyperglycaemia after the meal and then hypoglycaemia before the next meal.
  • Another reason for post-meal hyperglycaemia is underestimating the amount of carbohydrates in the meal and using an insufficient dose of rapid-acting insulin.
  • Corrective doses of rapid-acting insulin should primarily not be injected until 2-3 h after the preceding rapid-acting insulin injection.
    • Excessive correction between meals commonly sends blood glucose values on ”a rollercoaster ride”.
    • If corrective doses are injected though, to avoid a cumulative insulin effect the dose should only be half of what would be taken before a meal.
    • The glucose sensor arrow showing changes in blood glucose helps to assess the corrective dose.
    • Dose calculators included in insulin pumps and some rapid blood glucose meters and smart device applications take into consideration the amount of insulin left from the preceding rapid-acting insulin dose.
  • If a carbohydrate snack is eaten after a meal or between meals, it will naturally require a separate dose of rapid-acting insulin regardless of the time since the preceding dose, unless the snack is taken to prepare for physical exercise.

Continuous glucose monitoring and self-monitoring of blood glucose Continuous Glucose Monitoring Systems for Type 1 Diabetes Mellitus

  • Self-monitoring of blood glucose with a glucose sensor is useful for patients with insulin deficiency who are capable of utilizing this method.
    • It reduces the time in hypoglycaemia and increases the time in the blood glucose target range.
    • It facilitates self-monitoring and insulin replacement in case of varying deficiency.
    • It improves safety, coping in daily life and quality of life of people with diabetes and their relatives.
  • If continuous glucose monitoring is not used, 1-2 weeks of continuous glucose monitoring should still be done before seeing the doctor/nurse to plan the treatment.
  • A glucose sensor measures the glucose concentration in the subcutaneous tissue fluid.
    • The reading is not exactly the same as the blood glucose reading but sufficiently reliable to be used as the basis for insulin dosing.
    • If blood glucose levels are stable, the difference is approximately ± 10%.
    • It may be more if blood glucose levels are decreasing or increasing.
    • The glucose sensor arrow shows the direction and rate of change in blood glucose.
    • If the sensor reading is clearly too low or high or contradictory to the situation or the person's sensations, blood glucose should be checked from the fingertip.
  • The glucose sensor should be scanned and the reading checked before meals and before going to bed and also after meals, as necessary.
    • Further scanning or checking of readings should be done as considered individually necessary and on days of sickness, in association with physical exercise and before driving a motor vehicle.
    • A glucose sensor can be set to sound an alarm for low or high glucose levels.
  • If blood glucose is stable, before a meal, for instance, the reading provided by a glucose sensor corresponds sufficiently well with blood glucose levels to be used as the basis for injecting mealtime insulin.
  • Insulin doses, amounts of carbohydrates, physical exercise and any abnormal observations should be entered in the glucose sensor reader or application.
    • This should be done at least for several days at intervals that are suitable for the person for following the effectiveness of the treatment and before any treatment visits.
  • The data can be shared with the treating unit through a cloud server.
    • The report will give a good picture of the blood glucose balance and of the behaviour of blood glucose at different times of the day and in connection with different meals.
    • Insulin doses should be adjusted in the case of repeated changes in glucose levels.
  • If continuous glucose monitoring is not used, blood glucose should be monitored by traditional fingertip testing.
    • Paired evening and morning tests can be used to adjust the basal insulin dose.
    • Paired meal tests can be used to adjust the insulin-carbohydrate ratio for mealtime insulin.

Insulin treatment and diet

  • A diet conforming to the common dietary recommendations for promoting cardiovascular health, weight and blood glucose management should be followed.
  • No particular meal plans are necessary.
    • With modern regimes involving flexible multiple injections or pump therapy, the timing and size of meals can be chosen based on the person's needs.
  • Knowing how to assess carbohydrates is indispensable for people with diabetes so as to be able to inject appropriate amounts of rapid-acting insulin and avoid constant blood glucose fluctuation.
    • Amounts of carbohydrates and, consequently, doses of rapid-acting insulin vary from meal to meal depending on appetite, meal composition, energy requirements and preferences.
    • For most adults, it is sufficient to estimate the total carbohydrate amount in a meal to an accuracy of about 10 g.
    • Product information and carbohydrate tables or a carbohydrate application downloaded to a smart phone can be used for this.
  • If mealtime insulin is used in constant doses, the amounts of carbohydrates in different meals should stay the same.
    • In practice, however, amounts of carbohydrates vary and so do, consequently, blood glucose levels.
    • Patients and those taking care of them should be given unambiguous written instructions for adjusting insulin doses according to pre-meal blood glucose levels.
  • Guidance by a therapeutic dietitian is necessary if the person with diabetes:
    • has coeliac disease or significant food allergy (several central foodstuffs)
    • has several diseases requiring dietary treatment
    • has gastroparesis (disturbance of gastric emptying)
    • has an eating disorder
    • has moderate or severe kidney failure
    • is malnourished
    • follows a vegan or other vegetarian diet (particularly if physically very active)
    • has recently diagnosed type 1 diabetes.
  • Guidance by a therapeutic dietitian may also be necessary if the patient has problems with implementing the diet, is overweight and wishes to lose some weight or has problems with weight management or significant dyslipidaemia or is planning to become pregnant.

Physical exercise and insulin treatment

  • Regular physical exercise improves insulin sensitivity, decreases the need for insulin in those who have previously been less active, and has favourable effects on increased risks of cardiovascular disease.
  • Hypoglycaemia or fear of hypoglycaemia may prevent physical exercise.
    • It is important for health professionals to instruct their patients how to adjust insulin and carbohydrate dosage and how to interpret continuous glucose monitoring and self-monitoring of blood glucose appropriately in association with physical exercise.
  • Changes in blood glucose during physical exercise are affected by the type, duration and intensity of exercise and by how fit the person is, but also by numerous other factors: blood glucose before physical exercise, the amount of insulin that is active during exercise and during the following night, stress hormone levels associated with the exercise, glucose stored in muscles and in the liver, and food eaten before, during and after the exercise.
  • Physical exercise poses additional challenges to the control of glucose balance.
    • The dosage of insulin and carbohydrates in association with physical exercise should be learned with the help of continuous glucose monitoring or frequent self-monitoring of blood glucose.
    • In aerobic endurance exercise, blood glucose may fall too much during and after the exercise and during the following night.
      • The dose of basal insulin detemir or glargine, 100 units/ml, that is active during prolonged exercise can be reduced by 20-30 or even 50% depending on the strenuousness and duration of the exercise.
      • If physical exercise is taken within about 2 h from a meal, experience shows that the dose of rapid-acting insulin should be reduced by 20-50%.
      • After prolonged or intense physical exercise, the dose of basal insulin detemir or glargine, 100 units/ml, that is active during the night should be reduced by 10-20%.
    • In anaerobic muscle strengthening or interval-type exercise, blood glucose levels may increase in association with exercise or soon thereafter.
  • Pre-exercise blood glucose levels of 5-8 mmol/l are suitable for most people.
    • During exercise, about 20-60 g/h of extra carbohydrates are required depending on the intensity of the exercise and on any reduced insulin doses.

Hypoglycaemia

  • Hypoglycaemias that can be treated by the patient occur nearly every day.
  • Common causes include:
    • excessive amount of basal insulin acting during night-time
    • too large mealtime bolus in relation to carbohydrate intake
    • occasional administration error
    • delayed or missed meal with a too high concentration of circulating basal insulin
    • unexpected physical exertion with no reduction in the dose and no increase in carbohydrate intake
    • physical exercise not covered by dose reduction or extra carbohydrates during the maximum effect of the insulin dose
    • enhanced absorption associated with changing the injection technique or site
    • inadvertent intramuscular or intravenous injection
    • excessive alcohol intake and hangover (hepatic glucose production inhibited)
    • decreased insulin requirement in the case of remission or due to weight loss, renal insufficiency, hypothyroidism or adrenocortical insufficiency
  • Classification of hypoglycaemias
    • Mild: blood glucose 3.9-3.0 mmol/l, treated by the patient by eating fast carbohydrates.
    • Significant: blood glucose < 3.0 mmol/l; symptoms of hypoglycaemia can be detected but do not involve severely compromised functional capacity, and blood glucose can be corrected by the patient.
    • Severe: no particular blood glucose limit, functional capacity and thinking are affected and someone else is needed to correct the situation.
  • Symptoms of hypoglycaemia may change, be attenuated or completely missing in the case of longstanding type 1 diabetes or if the patient suffers from recurrent significant hypoglycaemias.
    • Continuous glucose monitoring is recommended if symptoms of hypoglycaemia are absent.
    • Hypoglycaemia awareness can be restored by raising the glucose target slightly so that levels below 4-5 mmol/l do not occur.
  • Hypoglycaemia is often followed by hyperglycaemia from excessive increase in carbohydrate intake and also by reactively increased blood glucose levels.
    • Insulin resistance due to hormones increasing blood glucose levels may last up to 24 hours after a hypoglycaemic episode.
    • Due to insulin resistance, a higher than usual rapid-acting insulin dose may be needed to correct the blood glucose level.
      • On the other hand, caution must be taken to avoid accumulation of insulin from repeated corrective doses - they can easily send blood glucose values on “a rollercoaster ride”.
    • For treatment, see Hypoglycaemia in a Patient with Diabetes.

Hyperglycaemia

  • There are several causes for blood glucose values exceeding the target level, and it is impossible, in practice, to control all such factors.
  • Classification of hyperglycaemias
    • High blood glucose: 10.0-13.9 mmol/l
    • Notably high blood glucose: > 13.9 mmol/l
  • It is important, in practice, to distinguish between transient and recurrent hyperglycaemia.
    • Transient hyperglycaemia will be spontaneously corrected or can be corrected by administering an additional dose of rapid-acting insulin.
    • The cause of recurrent elevation of blood glucose levels at a certain time of day or in association with a certain meal or certain activity must be investigated in more detail and the treatment adjusted accordingly.
  • Common causes of post-meal hyperglycaemia include amounts of carbohydrate assessed as too low or administration of rapid-acting insulin while eating or after eating, so that, depending on the amount of carbohydrates eaten, blood glucose levels usually increase too much 1-2 hours after eating and may decrease too much 3-4 hours after eating.
  • Acute diseases and the possibly associated bed rest, inflammation, stress and glucocorticoid treatment increase the need for insulin.
    • In patients with acute illness, blood glucose readings should initially be checked every (1-)2 hours.
    • Ensure adequate insulin administration, as well as adequate carbohydrate and fluid intake.
    • Additional doses of rapid-acting insulin should be administered every 2-4 hours, depending on blood glucose levels.
    • If there are ketones in the urine/blood, the need for insulin is increased.
    • If the illness is prolonged, the dose of basal insulin should also be increased, as necessary.
  • Glucocorticoids significantly affect glucose metabolism and may cause hyperglycaemia. Even an intra-articular glucocorticoid injection may increase blood glucose levels for up to several days.
  • Nausea and vomiting may be symptoms of ketoacidosis: in patients with insulin-treated diabetes and abdominal symptoms, blood glucose and ketones should always be checked with a rapid meter.
  • For ketoacidosis in adults, see Diabetic Ketoacidosis.

Guidance and support of self-care

  • Type 1 diabetes will be the person's constant companion for the rest of his/her life.
  • As the results of treatment and coping with diabetes are based on self-care and numerous daily decisions, guidance of self-care and supportive cooperation play a central role.
  • Find out about locally available services for patients (e.g. peer support, courses, meetings, information materials) and for professionals (e.g. guidance on patient education and support concerning e.g. treatment instructions, self-care, different phases of life)
  • For follow-up, see Follow-Up of Type 1 Diabetes.

    References

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    • Hirsch. I. Type 1 diabetes sourcebook. Peters A, Laffel L (ed.). Alexandria: American Diabetes Association / JDRF, 2013. pp. 293-317.
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