Type 1 diabetes: shared care, CGM, and annual review in AU general practice

Type 1 diabetes mellitus (T1DM) is an autoimmune condition requiring lifelong insulin. It affects approximately 120,000 Australians — about 0.5% of the population — and incidence is rising by around 3% each year. Peak onset is between 5 and 14 years, but adult-onset is increasingly recognised; many adults with slowly progressive autoimmune beta-cell failure are initially misdiagnosed with type 2 diabetes.

Care is led by an endocrinologist and diabetes team. The GP’s shared-care role is to be the consistent presence in a person’s care: coordinating the annual review checklist, managing comorbidities and mental health, supporting self-management, and ensuring sick day plans and driving requirements remain current.

A. Core clinical — the AU general-practice framework

What happens in type 1 diabetes

The immune system attacks and destroys the insulin-producing beta cells in the islets of Langerhans in the pancreas. Without insulin, cells cannot use glucose for energy. Blood glucose rises dangerously; simultaneously, without insulin signalling, the body breaks down fat, producing ketone bodies — in excess, this causes diabetic ketoacidosis (DKA).

A honeymoon phase — partial residual beta-cell function — may persist for months after diagnosis, temporarily reducing insulin requirements. This is transient; eventually beta-cell function is lost completely and lifelong insulin replacement is necessary.

Key autoantibodies — present in about 90% of people at diagnosis — include: GAD (anti-glutamic acid decarboxylase, most useful in adults), IA-2 (anti-tyrosine phosphatase), ZnT8 (zinc transporter 8), and insulin autoantibodies (particularly in children). Combined with a low or undetectable C-peptide level (confirming absent beta-cell function), these distinguish T1DM from type 2 diabetes and MODY (maturity-onset diabetes of the young, a monogenic form).

Insulin therapy — MDI and pump options

Multiple daily injections (MDI) — the most common regimen:

• Long-acting basal insulin once or twice daily: glargine (Lantus, Toujeo), detemir (Levemir), or degludec (Tresiba)
• Rapid-acting bolus insulin before each meal: aspart (NovoRapid, Fiasp), lispro (Humalog), or glulisine (Apidra)
• Insulin doses are adjusted using an insulin-to-carbohydrate ratio (ICR) and an insulin sensitivity factor (ISF/correction factor)

Insulin pump therapy (CSII) delivers continuous subcutaneous insulin via a pump worn on the body, with boluses programmed at mealtimes. Pump therapy suits motivated patients with recurrent hypoglycaemia, dawn phenomenon, active lifestyles, pregnancy, or children who struggle with injection schedules.

Hybrid closed-loop systems (“artificial pancreas”) integrate a CGM sensor with an insulin pump and an algorithm that automatically adjusts basal insulin delivery in response to real-time glucose readings. Systems include Tandem t:slim X2 with Control-IQ, Medtronic 780G, and Omnipod 5. Multiple RCTs — including the DCCT landmark trial and more recent closed-loop studies — confirm that tighter glucose control reduces both microvascular and cardiovascular complications over time.

Continuous glucose monitoring (CGM)

CGM measures glucose every one to five minutes via a subcutaneous sensor, alerting to rising or falling glucose before symptomatic hypoglycaemia develops. Dexcom G6 and G7 are factory-calibrated 10-day sensors; FreeStyle Libre 2 and 3 are 14-day sensors with integrated alarms in the newer models.

The NDSS has subsidised CGM for all Australians with type 1 diabetes since 1 July 2022 — previously limited to children and those with complex management. Registration with the NDSS (via Diabetes Australia or a state diabetes organisation) is the first step. Any person with type 1 diabetes not yet using CGM should be supported to register and access this subsidy.

Glycaemic targets

Per Australasian Diabetes Society (ADS) and eTG:

• HbA1c < 7.0% (53 mmol/mol) — typical adult target
• HbA1c < 6.5% — pre-pregnancy and during pregnancy
• HbA1c 8–8.5% — appropriate for older adults with frailty, hypoglycaemia unawareness, or limited life expectancy

CGM-based targets:

• Time in range (TIR) > 70% (glucose 3.9–10.0 mmol/L)
• Time below range (TBR) < 4% (below 3.9 mmol/L)
• Time very below range < 1% (below 3.0 mmol/L)

Acute complications

Hypoglycaemia — blood glucose below 3.9 mmol/L — is the most immediate danger.

Mild (person can self-treat): 15 g fast-acting carbohydrate (jelly beans, glucose tablets, fruit juice or soft drink 150–200 mL), wait 15 minutes, retest, repeat if needed. Follow with a complex carbohydrate snack when glucose is stable.

Severe (requires assistance from another person): buccal glucose gel or glucagon. Nasal glucagon spray (Baqsimi 3 mg) is easier for bystanders to administer than the traditional intramuscular injection (GlucaGen 1 mg), and should be accessible to family members and carers of anyone with type 1 diabetes.

Hypoglycaemia unawareness — loss of the warning symptoms of low blood glucose — is dangerous and requires specialist review. CGM with alarms and pump low-glucose suspend features significantly reduce severe hypoglycaemia events in those with impaired awareness.

Diabetic ketoacidosis (DKA) — hyperglycaemia, metabolic acidosis (pH below 7.3, bicarbonate below 15 mmol/L), and ketosis (blood beta-hydroxybutyrate above 3 mmol/L) — is a medical emergency. Common precipitants are insulin omission (the most frequent cause), intercurrent illness, and pump failure. Never stop insulin in type 1 diabetes, even when unwell and not eating. Every person with type 1 diabetes should have a written sick day plan.

B. Annual complication review — the GP checklist

Annual structured review of complications is the core contribution of general practice to shared diabetes care. The following should be completed at least once per year per ADS and RACGP:

Glycaemic control:

• HbA1c
• CGM download review (time in range, low events, pattern analysis)

Cardiovascular risk:

• Blood pressure (target < 130/80 mmHg)
• Fasting lipids (LDL target < 2.0 mmol/L, consider statin from age 30–40)
• Smoking status

Kidney function:

• Urine albumin-to-creatinine ratio (UACR) — first morning void; annual from diagnosis
• Serum creatinine and eGFR
• ACE inhibitor or ARB indicated if microalbuminuria is confirmed (UACR ≥ 3 mg/mmol) — even in normotensive patients, to slow nephropathy progression

Eye screening:

• Retinal photography or dilated fundoscopy — annual from five years after diagnosis in adults; before conception and during pregnancy
• KeepSight registry provides a recall system for retinal screening

Neuropathy:

• 10 g monofilament test on the soles of both feet
• 128 Hz tuning fork for vibration sense at the hallux
• History of numbness, burning, pins and needles, orthostatic symptoms, bowel or bladder change

Foot examination:

• Pulses (dorsalis pedis, posterior tibial)
• Skin integrity, callus, ulcer, nail health, deformities

Mental health:

• Depression screening (PHQ-9)
• Diabetes distress (Problem Areas in Diabetes scale, PAID) — a distinct concept from depression; very common and under-recognised
• Eating disorders — particularly insulin omission for weight loss (“diabulimia”) in adolescent and young adult women — requires specialist team involvement
• Anxiety, particularly hypoglycaemia-related fear

Autoimmune comorbidities:

• TSH — autoimmune thyroid disease (Hashimoto’s or Graves’) affects 15–25% of people with type 1 diabetes
• TTG-IgA coeliac serology — coeliac disease affects 5–10% of T1DM; relevant to glycaemic control and nutrition

Vaccinations:

• Annual influenza vaccination
• COVID-19 boosters as per current ATAGI schedule
• Pneumococcal vaccination (PCV20 or PCV13 + PPSV23)
• Herpes zoster vaccine (Shingrix — non-live; appropriate from age 18 if immunocompromised)

C. Evidence appraisal — key points for general practice

CGM is standard care. Multiple RCTs confirm CGM reduces HbA1c and severe hypoglycaemia rates. The NDSS subsidy makes it accessible. If a patient with type 1 diabetes is not using CGM, ask why, and help address the barrier.

SGLT2 inhibitors are not recommended for type 1 diabetes in Australia. Empagliflozin and dapagliflozin carry Authority-required PBS listing for type 2 diabetes and CKD/heart failure indications — these indications do not include type 1 diabetes. The risk of euglycaemic diabetic ketoacidosis (DKA occurring without markedly elevated blood glucose, and therefore easily missed) is significantly increased in type 1 diabetes. SGLT2 inhibitors should not be prescribed for type 1 diabetes outside specialist-supervised research or compassionate access contexts.

GLP-1 receptor agonists in type 1 diabetes — evidence exists in selected obese patients but the drugs are off-label and not PBS-approved for this indication in Australia. Specialist context only.

D. Australian operations

NDSS and PBS access

The National Diabetes Services Scheme (NDSS) (phone 1800 637 700) provides subsidised access to: blood glucose strips, lancets, syringes, pen needles, insulin pump consumables, and CGM sensors for all Australians with type 1 diabetes. Free registration is through Diabetes Australia or a state diabetes organisation.

Insulin (all forms) is PBS Authority Required (Streamlined) for diabetes mellitus. Glucagon (GlucaGen IM and Baqsimi nasal) are general PBS schedule. ACE inhibitors and ARBs are general PBS.

The Insulin Pump Program (IPP) provides subsidised insulin pump access for paediatric patients in most states; adult access is more variable, often requiring private health insurance, and is an area of ongoing advocacy by JDRF Australia.

GP care planning — MBS

Chronic complex type 1 diabetes qualifies for:

• GPCCMP (MBS items 965 / 967) — chronic condition management plan with review; enables allied health referrals
• Allied health visits under GPCCMP — diabetes educator (item 10951), accredited practising dietitian (item 10954), exercise physiologist (item 10968), podiatrist (item 10960) — up to five combined visits per calendar year
• Retinal photography (MBS item 12325) for diabetes eye check
• Mental Health Treatment Plan (MBS items 2715 / 2717) — for comorbid depression, anxiety, or eating disorders

Driving requirements

Per Austroads Assessing Fitness to Drive 2022, people with type 1 diabetes on insulin driving a private vehicle must:

• Check blood glucose (or CGM reading confirmed by blood glucose meter) and confirm ≥5 mmol/L before every drive
• Keep glucose in the vehicle at all times
• Recheck every two hours on journeys over two hours
• Stop driving immediately if glucose falls below 5 mmol/L; treat; wait 45 minutes before resuming
• Report severe hypoglycaemia while driving to the licensing authority

Commercial licence (truck, bus, taxi, heavy vehicles) requirements are significantly more restrictive and require specialist endocrinology assessment.

Australian patient resources

• NDSS — registration, education, subsidised supplies, helpline
• Diabetes Australia — peak body; advocacy, education, state organisations
• JDRF Australia — research, peer support, T1D Family Centre, closed-loop advocacy
• HealthDirect — Type 1 diabetes

E. Special populations

Pregnancy. Pre-conception care is essential: achieve HbA1c below 6.5% before conception; start folate 5 mg daily; obtain retinal review before and during pregnancy; optimise CGM and consider pump initiation with specialist team. Insulin requirements increase throughout pregnancy. Closed-loop systems are showing benefit in pregnancy outcomes in emerging trial data. Gestational endocrinology and shared maternity care are required.

Children and adolescents. Paediatric diabetes team-led care; pump and CGM access is well-supported. Transition to adult services is a high-risk period — young people commonly disengage and glycaemic control deteriorates. Eating disorders (including “diabulimia”) are most prevalent in this group. General practice plays a supportive role during transition.

Older adults. Relaxed glycaemic targets (HbA1c 8–8.5%) are appropriate in the context of frailty, cognitive impairment, or limited life expectancy, where the risks of hypoglycaemia outweigh the long-term microvascular benefits of tight control. Severe hypoglycaemia is associated with cognitive harm. Deprescribing of insulin may be relevant in end-of-life care.

Sport and exercise. Exercise lowers blood glucose and increases hypoglycaemia risk during and after activity — particularly after prolonged aerobic exercise. Strategies include reducing basal insulin, consuming carbohydrate before and during exercise, and checking CGM alerts. CGM is particularly useful during sport.

When to escalate

Send to emergency department immediately for:

• Suspected DKA — blood glucose above 14 mmol/L, blood ketones above 1.5 mmol/L, vomiting, drowsiness, or Kussmaul breathing (deep, sighing respirations)
• Severe hypoglycaemia with altered consciousness — administer glucagon while calling 000
• Any unexplained deterioration in a person with type 1 diabetes

Refer to endocrinologist urgently when:

• HbA1c is above 9% despite current management
• Recurrent severe hypoglycaemia or significant hypoglycaemia unawareness
• Preparing for pregnancy or newly pregnant
• Considering insulin pump or closed-loop system
• Suspected LADA in an adult initially diagnosed with type 2 diabetes — autoantibodies and C-peptide will guide the diagnosis

What this article is and is not

This article draws on current Australian guidelines — Australasian Diabetes Society, NDSS, Therapeutic Guidelines (eTG), RACGP, and Diabetes Australia resources — to provide general health information about type 1 diabetes and shared care with general practice. It is not personal medical advice and does not create a doctor–patient relationship.

All decisions about insulin dose adjustments, choice of technology, and specialist referral are made with your diabetes team and GP based on your individual management plan.

For consumer-friendly information: NDSS, Diabetes Australia, JDRF Australia, HealthDirect.

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Sources cited

1. Australasian Diabetes Society — Type 1 diabetes management
2. NDSS — National Diabetes Services Scheme
3. Therapeutic Guidelines (eTG) — Type 1 diabetes
4. RACGP — Diabetes management resources
5. Diabetes Australia
6. JDRF Australia
7. HealthDirect — Type 1 diabetes
8. ADA Standards of Care in Diabetes
9. DCCT Research Group — NEJM 1993