Type 1 Diabetes mellitus, in adults

E10.9

Type 1 diabetes mellitus is a rare condition and should be diagnosed and monitored at hospital level. Only stable patients may be down referred for chronic medicines.

MONITORING FOLLOWING DOWN REFERRAL

At every visit:

  • Finger-prick blood glucose.
  • Weight.
  • Blood pressure.

Annually:

  • HbA1c, one month before next hospital appointment.

TARGETS FOR CONTROL

Glycaemic targets for control:

Patient type Target HbA1c Target FBG* Target PPG*
  • Young, low risk

  • Newly diagnosed

  • No CVS disease
    		•  < 6.5% 4.0–7.0 mmol/L 4.4–7.8 mmol/L
  • Majority of patients
    		•  < 7.0% 4.0–7.0 mmol/L 5.0–10.0 mmol/L
  • Elderly

  • High risk

  • Hypoglycaemic unawareness

  • Poor short-term prognosis
    		•  < 7.5% 4.0–7.0 mmol/L < 12.0 mmol/L

    * FBG: fasting blood glucose; PPG: post prandial blood glucose.


    Non-glycaemic targets:

    • Body mass index ≤25 kg/m².
    • BP <140/90 mmHg.

    The increased risk of hypoglycaemia must always be weighed against the potential benefit of reducing microvascular and macrovascular complications.

    MEDICINE TREATMENT

    As type 1 diabetes mellitus usually presents with diabetic ketoacidosis, treatment is usually initiated with insulin and the patient is stabilised at hospital level. Oral anti-diabetic medicines should not be used to treat type 1 diabetics.
    Insulin dose requirements will decrease as kidney disease progresses.

    Types of insulin

    • Insulin, short acting, SC, three times daily, 30 minutes before meals.
      • Regular human insulin.
      • Onset of action: 30 minutes.
      • Peak action: 2–5 hours.
      • Duration of action: 5–8 hours.
    • Insulin, intermediate acting, SC, once or twice daily usually at night at bedtime, approximately 8 hours before breakfast.
      • Intermediate acting insulin.
      • Onset of action: 1–3 hours.
      • Peak action: 6–12 hours.
      • Duration of action: 16–24 hours.
    • Insulin, biphasic, SC, once or twice daily.
      • Mixtures of regular human insulin and intermediate acting insulin in different proportions, e.g. 30/70 (30% regular insulin and 70% intermediate acting insulin).
      • Onset of action: 30 minutes.
      • Peak action: 2–12 hours.
      • Duration of action: 16–24 hours.

    Insulin regimens

    Basal bolus regimen
    All type 1 diabetics should preferentially be managed with the “basal bolus regimen” i.e. combined intermediate-acting (basal) and short-acting insulin (bolus). This consists of pre-meal, short-acting insulin and bedtime intermediate-acting insulin not later than 22h00.

    The initial total daily insulin dose:

    • 0.6 units/kg body weight.

    The total dose is divided into:

    • 40–50% basal insulin
    • The rest as bolus insulin, split equally before each meal.

    Adjust dose on an individual basis.

    Pre-mixed insulin

    Twice daily pre-mixed insulin, i.e. a mixture of intermediate- or short- acting insulin provides adequate control, when used with at least daily blood glucose monitoring. It is a practical option for patients who cannot monitor blood glucose frequently.

    Education related to insulin therapy

    • Types of insulin.
    • Injection technique and sites of injection.
    • Insulin storage.
    • Recognition and treatment of acute complications, e.g. hypoglycaemia and hyperglycaemia.
    • Diet:
      • Meal frequency, as this varies according to the type and frequency of insulin, e.g. patients may need a snack at night, about 3–4 hours after the evening meal.
      • Consistent carbohydrate intake for patient receiving fixed mealtime doses of insulin.
    • Self-monitoring of blood glucose and how to self-adjust insulin doses.

    Drawing up insulin from vials

    • Clean the top of the insulin bottle with an antiseptic swab.
    • Draw air into the syringe to the number of marks of insulin required and inject this into the bottle; then draw the required dose of insulin into the syringe.
    • Before withdrawing the needle from the insulin bottle, expel the air bubble if one has formed.

    Injection technique

    • The skin need not be specially cleaned.
    • Repeated application of antiseptics hardens the skin.
    • Stretching the skin at the injection site is the best way to obtain a painless injection. In thin people it may be necessary to pinch the skin between thumb and forefinger of one hand.
    • The needle should be inserted briskly at almost 90° to the skin to almost its whole length (needles are usually 0.6–1.2 cm long).
    • Inject the insulin.
    • To avoid insulin leakage, wait 5–10 seconds before withdrawing the needle.
    • Injection sites must be rotated to avoid lipohypertrophy.

    Prefilled pens and cartridges
    In visually impaired patients and arthritic patients, prefilled pens and cartridges may be used.

    Home blood glucose monitoring
    Patients on basal/bolus insulin should measure glucose 3-4 times daily.
    Once patient is stable, reduce the frequency of monitoring.

    LoE III

    REFERRAL

    All patients.