Cystic fibrosis in adults: shared care in Australian general practice

Cystic fibrosis — a condition transformed by modern therapy

Cystic fibrosis (CF) is an autosomal-recessive condition caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene on chromosome 7. Defective CFTR protein produces abnormally thick, sticky mucus that obstructs and damages the airways, pancreas, liver, intestines, and reproductive tract. Cystic Fibrosis Australia estimates approximately 3,800 Australians are living with CF — about one in every 2,500 newborns — with the Caucasian-Australian population carrying a carrier rate of approximately one in 25.

The story of CF has changed dramatically in the past decade. Where median survival was roughly 30 years in the 1990s, children born after 2000 who receive access to CFTR modulator therapy now have a predicted median survival exceeding 50 years. For adults living with CF — especially those diagnosed in the pre-modulator era — general practice plays a critical shared-care role: managing routine health, coordinating vaccinations, screening for complications, supporting mental health and family planning, and providing the first point of contact for acute presentations.

This article covers adult CF shared care from the Australian general practice perspective, drawing on Therapeutic Guidelines (eTG), Cystic Fibrosis Australia, the Thoracic Society of Australia and New Zealand (TSANZ), and landmark clinical trials.

A. Core clinical — the AU general practice framework

What to ask at a shared-care review

An adult patient with established CF attends the specialist CF multidisciplinary team quarterly at minimum. When they present to general practice, the purpose varies — routine GP issues, acute illness, mental health support, family planning, paperwork (NDIS, DSP), or an acute pulmonary exacerbation.

At a routine review, eTG Respiratory and Cystic Fibrosis Australia guidelines suggest focusing on:

• Pulmonary status — exercise tolerance, sputum colour and volume, frequency of exacerbations, current antibiotic courses.
• Nutrition — weight and BMI (targets: ≥22 kg/m² in women, ≥23 kg/m² in men), appetite, gastrointestinal symptoms, pancreatic enzyme dosing.
• Glycaemic surveillance — CF-related diabetes (CFRD) is best detected by annual oral glucose tolerance testing (OGTT); HbA1c significantly underestimates CFRD and should not be relied upon as the sole screen.
• Bone health — fragility fractures, height loss; DEXA scanning biennially from age 18.
• Mental health — depression and anxiety are substantially more prevalent in CF than in the general population; suicidality risk is elevated; use PHQ-9 and GAD-7 at every routine visit.
• Modulator adherence and side effects — liver function test (LFT) monitoring for those on Trikafta; mood or sleep changes should prompt clinical discussion.
• Vaccinations — annual influenza, pneumococcal (PCV13 once, PPV23 five-yearly), COVID-19 boosters per ATAGI, hepatitis A (given liver involvement), and age-appropriate standard schedule.
• Family planning — partner CFTR carrier testing, reproductive options, contraception, pre-conception counselling.

Examination

Relevant examination includes weight and height (BMI), digital clubbing, SpO₂ at rest, chest auscultation (crackles over bronchiectatic regions, wheeze), abdominal palpation (hepatomegaly or splenomegaly in CF liver disease, a right iliac fossa mass in distal intestinal obstruction syndrome), and depression and anxiety screening.

Investigations

Routine annual workup includes spirometry (FEV1 and FVC), sputum culture and sensitivity (noting Pseudomonas aeruginosa, Staphylococcus aureus, MRSA, non-tuberculous mycobacteria, Burkholderia cepacia complex, and Aspergillus fumigatus), full blood count, LFTs, renal function, electrolytes, OGTT for CFRD (not HbA1c alone), vitamins A, D, E, and K levels, iron studies, and albumin. DEXA bone density is performed every two years from age 18, or annually if osteoporosis is confirmed.

For patients presenting with features suggesting undiagnosed CF or a CFTR-related disorder — such as a male with infertility (congenital bilateral absence of the vas deferens, CBAVD, occurs in approximately 95% of males with CF), recurrent pancreatitis, or idiopathic bronchiectasis — sweat chloride testing (>60 mmol/L is diagnostic) and full-sequence CFTR genetic testing via a specialist are appropriate first steps.

Common presentations to the GP

• Pulmonary exacerbation — increased cough, change in sputum colour or volume, declining exercise tolerance, haemoptysis, or fever. Most exacerbations require antibiotic therapy guided by sputum culture; IV therapy is often needed for Pseudomonas exacerbations.
• Acute abdominal pain — distal intestinal obstruction syndrome (DIOS) presents with colicky right-sided pain, constipation, and sometimes a palpable right iliac fossa mass; it can mimic appendicitis. First-line management is oral polyethylene glycol lavage or N-acetylcysteine; imaging to exclude appendicitis is appropriate.
• New glycaemic symptoms — polyuria, polydipsia, or weight loss; request OGTT rather than HbA1c and refer to the CF team for insulin initiation.
• Mental health presentation — CF-specific psychological distress responds to a Mental Health Treatment Plan referral to a psychologist experienced with chronic illness.

B. The CFTR modulator revolution

CFTR mutations are grouped by functional class — from absent protein production (Class I, such as G542X) to impaired protein processing (Class II, the most common being F508del) to gating defects (Class III, such as G551D). CFTR modulators correct or potentiate the defective protein depending on mutation class.

Elexacaftor/tezacaftor/ivacaftor (Trikafta) is the triple-combination modulator that has transformed care for approximately 90% of the Australian CF population — all those carrying at least one F508del allele or another responsive mutation. In the pivotal Middleton NEJM 2019 trial, Trikafta produced a 14.3 percentage-point absolute increase in FEV1 percentage predicted, a 63% reduction in pulmonary exacerbations, significant weight gain, and near-normalisation of sweat chloride — effects that have proven durable over open-label extension periods. A companion trial by Heijerman et al. (Lancet 2019) in F508del homozygous patients confirmed comparable benefit.

Trikafta has been listed on the Australian PBS under Section 100 (Highly Specialised Drugs) since 2022, requiring specialist initiation on a restricted authority. It is administered twice daily orally with a fat-containing meal. Side effects include elevated LFTs (monitor three-monthly initially), rash, headache, elevated CK, and — reported by a subset — mood changes or worsening depression, which require monitoring.

For the approximately 10% of patients whose mutations are not modulator-responsive (primarily Class I nonsense mutations such as G542X and W1282X), current CFTR modulator therapy is not effective. Research into readthrough agents and gene-editing approaches is active but has not yet reached clinical practice in Australia.

The modulator era has not eliminated the need for conventional airway therapy. Elkins et al. (NEJM 2006) demonstrated that inhaled hypertonic saline 7% reduces exacerbation frequency and lung function decline — dornase alfa (Pulmozyme) and mannitol inhalation powder (Bronchitol) are PBS Section 100 listed as complementary mucolytics. Azithromycin immunomodulation (oral, three times weekly) for patients with chronic Pseudomonas infection reduces exacerbations, per Saiman et al. (NEJM 2003), though NTM screening is required before initiation.

Daily airway clearance physiotherapy — using oscillating positive expiratory pressure devices (Acapella, Aerobika, Flutter), postural drainage, and exercise — remains a cornerstone of CF management. It is typically performed twice daily throughout life, independent of modulator status.

C. Managing CF complications in general practice

CF-related diabetes

CFRD results from insulin insufficiency caused by progressive destruction of islet cells by fibrosis of the exocrine pancreas. Fasting blood glucose is frequently normal even when post-prandial glucose excursions are significant, making HbA1c an unreliable screen. Annual OGTT from age 10 is the recommended detection method per Cystic Fibrosis Australia and international CF guidelines.

Treatment is insulin. Avoiding weight loss is essential in CF — contrary to standard advice in type 2 diabetes — because CF nutrition targets are weight maintenance at BMI ≥22 (women) or ≥23 (men). Oral hypoglycaemic agents are not first-line for CFRD. Continuous glucose monitoring is increasingly standard in specialist centres.

Bone health

CF-related osteoporosis results from fat-soluble vitamin D malabsorption, chronic airway inflammation, corticosteroid use, and — historically — poor nutrition. CFTR modulators improve bone density over time but do not completely reverse cumulative deficits. The GP role includes ensuring biennial DEXA from age 18, optimising calcium and vitamin D (using ADEK-specific CF formulations where available), referring for bisphosphonate therapy (zoledronate or alendronate) if osteoporosis is confirmed, and encouraging weight-bearing exercise throughout adult life.

CF liver disease

CF liver disease — biliary cirrhosis from bile duct obstruction by thick bile — affects approximately 30% of CF patients. Annual LFTs and hepatic ultrasound surveillance are coordinated by the CF specialist team. Portal hypertension features — oesophageal varices, splenomegaly, ascites — require urgent specialist review. GPs should not miss splenomegaly on routine abdominal examination in a CF patient with unremarkable respiratory function, as liver disease can progress silently.

Mental health

Depression and anxiety prevalence in CF is two to three times higher than the general population, with elevated suicidality risk confirmed in multiple registry analyses. PHQ-9 and GAD-7 screening at every general practice consultation provides the baseline for clinical action. A Mental Health Treatment Plan (MBS items 2715/2717) provides access to 10 subsidised sessions per year with a psychologist — aim for a practitioner experienced with chronic illness. Antidepressants are safe alongside Trikafta with standard precautions.

Pulmonary infection management

New Pseudomonas aeruginosa acquisition is treated with eradication regimens — inhaled tobramycin (TOBI Podhaler) for 28 days, or colistin/aztreonam lysine — coordinated with the CF centre. Chronic Pseudomonas suppression typically uses alternating monthly inhaled antibiotic cycles (tobramycin/aztreonam/colistin). Acute exacerbations require sputum culture and sensitivity, CRP, spirometry (to gauge decline from baseline), and antibiotic selection guided by microbiology. Oral therapy (ciprofloxacin for mild Pseudomonas exacerbations, or appropriate agents for S. aureus) is appropriate for mild exacerbations without systemic features; IV therapy — typically piperacillin-tazobactam combined with tobramycin for Pseudomonas — is coordinated with or through the CF centre for moderate-to-severe episodes.

D. Australian operations

CF specialist centres

Adult CF care in Australia is delivered through specialist multidisciplinary centres with integrated physiotherapy, dietetics, endocrinology, gastroenterology, psychology, social work, and nursing. The main adult centres are:

• Victoria: Alfred Hospital (Australia’s largest adult CF programme)
• NSW: Royal Prince Alfred Hospital, Westmead Hospital
• Queensland: Royal Brisbane and Women’s Hospital, Prince Charles Hospital
• WA: Sir Charles Gairdner Hospital
• SA: Royal Adelaide Hospital
• Tasmania: Royal Hobart Hospital

General practice provides care between specialist visits and coordinates community services. TSANZ and Cystic Fibrosis Australia both publish guidance for the GP role in CF shared care.

MBS and PBS

• MBS 965/967 — GP Chronic Condition Management Plan (GPCCMP, introduced July 2025, replacing GPMP/TCA items 721/723) — covers CF for allied health referrals: dietitian, physiotherapist, psychologist (via Mental Health Care Plan MBS 2715/2717 for the psychology pathway).
• PBS Section 100 (Highly Specialised Drugs): elexacaftor/tezacaftor/ivacaftor (Trikafta), dornase alfa (Pulmozyme), inhaled tobramycin (TOBI Podhaler), aztreonam lysine (Cayston), mannitol inhalation powder (Bronchitol) — all specialist-initiated, restricted authority. GPs are not the initiating prescriber but can understand eligibility criteria to support referral pathways. PBS details at pbs.gov.au.
• PBS Authority prescriptions: pancreatic enzyme replacement (Creon — Authority), ursodeoxycholic acid (Authority for CF liver disease), azithromycin, insulin, and standard antibiotics per culture.
• MBS 12521/12525 — DEXA bone density (every two years per CF guidelines).
• NDIS — CF with significant functional impairment qualifies for supports including physiotherapy, assistive technology, and transport; the GP supporting report and NDIS planner advocacy are important GP roles.
• Disability Support Pension (DSP) — available for advanced CF with work-limiting impairment; GP-completed medical evidence forms are required.

E. Special populations

Paediatric to adult transition

The transition from paediatric to adult CF care occurs around age 16–18, ideally with a structured transition programme co-managed between paediatric and adult services. Young adults face new challenges — independent medication management, reproductive decision-making, and employment and insurance navigation. The adult CF centre coordinates transition; general practice provides continuity and is often the first contact for mental health concerns during this vulnerable period.

Pregnancy

Women with CF can become pregnant, though fertility is reduced by thick cervical mucus and other factors. CFTR modulator continuation during pregnancy is now standard practice for most eligible patients, supported by growing international registry data. Pregnancy in patients with advanced CF (FEV1 <50% predicted) carries significant risk and requires co-management between the CF specialist team and a high-risk obstetric service. Gestational CFRD monitoring is coordinated carefully throughout pregnancy.

Males with CBAVD and infertility

Approximately 95% of males with CF have congenital bilateral absence of the vas deferens, resulting in obstructive azoospermia. Sperm production in the testes remains intact. Testicular or epididymal sperm extraction (TESE/MESE) combined with IVF/ICSI offers good success rates. Partner CFTR carrier testing (given the one-in-25 population carrier rate) is essential before proceeding with assisted reproduction. GPs are often the initial point for this conversation and can provide referral to a reproductive specialist with CF experience.

Aboriginal and Torres Strait Islander Australians

CF is less prevalent in Aboriginal and Torres Strait Islander populations because of differing CFTR mutation spectra — historical newborn screening panels were less sensitive for non-European variants. Updated panels now include a broader range of mutations. Cultural sensitivity, community-specific support pathways, and use of RACGP Aboriginal and Torres Strait Islander Health guidance are relevant for this community.

Older adults with CF

Patients now in their 40s and 50s carry cumulative lung damage from the pre-modulator era. Commencing or continuing CFTR modulator therapy can still provide meaningful benefit, though FEV1 gains may be modest against established bronchiectasis. Cardiovascular risk surveillance, polypharmacy review, and frailty assessment become increasingly important as this cohort ages. The Lung Foundation Australia and Cystic Fibrosis Australia provide consumer-facing resources appropriate for older patients navigating this transition.

When to escalate

Refer or contact the CF centre when:

• Moderate-to-severe pulmonary exacerbation — FEV1 decline from baseline, hypoxaemia (SpO₂ <93%), or systemic features (rigors, temperature >38.5°C) — for IV antibiotics in most cases.
• Haemoptysis — minor streaking is common and does not always require escalation; massive haemoptysis (>240 mL over 24 hours) is life-threatening and requires emergency referral.
• Suspected or confirmed CFRD — new hyperglycaemic symptoms or a positive OGTT — for specialist insulin initiation.
• Respiratory failure — declining SpO₂ or exercise capacity, rising CO₂ on blood gas — for CF centre urgent review, oxygen therapy initiation, and lung transplant assessment if FEV1 approaches 30% predicted.
• CF liver disease complications — oesophageal varices, portal hypertension, ascites — via gastroenterology and hepatology through the CF centre.
• Mental health emergency — suicidal ideation — Emergency Department or Lifeline 13 11 14.
• New atypical CF or CFTR-related disorder suspected — for sweat chloride testing, CFTR genetic analysis, and formal multidisciplinary workup.
• Lung transplant assessment — FEV1 <30% predicted, rapid decline trajectory, recurrent severe exacerbations, oxygen dependence — refer to a transplant centre (Alfred Melbourne, RPA Sydney, Prince Charles Brisbane, Sir Charles Gairdner Perth).

What this article is and is not

This is general health information drawn from current Australian guidelines — Therapeutic Guidelines (eTG), Cystic Fibrosis Australia, the TSANZ, and RACGP resources — alongside published landmark trials. It is not personal medical advice and does not create a doctor–patient relationship. Decisions about modulator eligibility, CFRD management, transplant referral, and specific antibiotic therapy are made collaboratively by the treating CF specialist team and the patient’s GP.

For consumer-friendly information: Cystic Fibrosis Australia, HealthDirect — Cystic Fibrosis, Better Health Channel.

For acute respiratory or mental health emergencies: Emergency services 000, Lifeline 13 11 14, Beyond Blue 1300 22 4636, 13YARN 13 92 76.

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Sources cited

1. Cystic Fibrosis Australia
2. Thoracic Society of Australia and New Zealand (TSANZ)
3. Therapeutic Guidelines (eTG) — Respiratory
4. RACGP
5. PBS Section 100 — Trikafta and CF modulators
6. ATAGI — Immunisation for people with chronic disease
7. HealthDirect — Cystic Fibrosis
8. Better Health Channel
9. Lung Foundation Australia
10. Middleton PG et al. — Elexacaftor–tezacaftor–ivacaftor for CF (NEJM 2019)
11. Heijerman HGM et al. — Trikafta in CF (Lancet 2019)
12. Elkins MR et al. — Hypertonic saline in CF (NEJM 2006)
13. Saiman L et al. — Azithromycin for CF with chronic Pseudomonas (NEJM 2003)