Treatment and Management of Non-infectious Diseases

Q1 — Sample Band 6 response (8 marks), annotated

To evaluate a treatment means to provide a balanced judgement of its effectiveness, costs, limitations, and appropriateness for specific patient groups — not merely listing its properties. [1 — definition of evaluation]

CVD — Statins vs CABG: Statins competitively inhibit HMG-CoA reductase in hepatocytes, reducing LDL synthesis and causing liver cells to upregulate LDL receptors — achieving 25–35% relative risk reduction in major cardiovascular events (table). They cost $60–480 per year on PBS and are prescribed by GPs in all settings, making them highly accessible in rural and urban Australia alike. CABG surgically grafts a blood vessel around a blocked coronary artery, restoring myocardial blood flow, and produces superior outcomes in severe multi-vessel disease where medication alone is inadequate. The patient cost is approximately zero under Medicare; however, the procedure costs $40,000–50,000 total and requires a cardiothoracic surgeon, hospital admission, and weeks of recovery — making it less accessible in rural areas and inappropriate for elderly patients with high surgical risk. Statins are appropriate for all CVD patients as ongoing secondary prevention; CABG is appropriate specifically for severe multi-vessel disease not adequately managed by pharmacological treatment. The two are complementary — CABG patients require statins post-surgery because CABG bypasses the blockage but does not treat the underlying atherosclerotic disease. [2 — mechanisms + effectiveness by patient group + cost + accessibility for CVD, stated when each appropriate]

T2D — Metformin vs lifestyle management: In early-stage T2D, Australian Diabetes Society guidelines recommend lifestyle modification first — structured dietary change (reduce refined carbohydrates, increase fibre) and at least 150 minutes/week of aerobic exercise. Exercise activates GLUT4 translocation independently of insulin, directly lowering blood glucose; weight loss >15% can achieve sustained T2D remission (table). This has very low direct financial cost, but requires sustained behavioural change, time, food security, and support services — creating socioeconomic barriers for low-income or time-constrained patients. Metformin is added if lifestyle intervention does not achieve target HbA1c below 7.0%. It activates AMPK in hepatocytes, reduces gluconeogenesis, and improves insulin sensitivity — lowering HbA1c by 1–2% at a PBS cost of approximately $72/year; it does not restore beta-cell function. Lifestyle management is appropriate as first-line for early-stage patients who can sustain it; metformin is appropriate when lifestyle change is insufficient, impractical, or adherence is limited. [2 — mechanisms + effectiveness + cost + feasibility for T2D, stated when each appropriate]

Data from the table demonstrate this clearly: CABG and lifestyle management may be "most biologically effective" in their respective disease contexts, but both have significant access barriers — surgical risk and rural geography for CABG; socioeconomic barriers for sustained lifestyle change. Statins ($60–480/year) and metformin ($72/year) are less dramatic interventions but are universally accessible through PBS, requiring only a GP prescription. [1 — uses specific data]

The most appropriate treatment is not always the most biologically effective option — it is the most effective treatment that a specific patient can safely access, afford, and maintain long-term. A rural 80-year-old with CVD may benefit more from optimised statin therapy than from a CABG they cannot safely undergo or access; a time-poor T2D patient with poor food security may require metformin even if lifestyle modification would be more effective if sustained. [2 — overall evidenced judgement linking effectiveness + cost + accessibility + patient factors]

Marking criteria.

• 1 mark — Defines evaluation as balanced judgement of effectiveness, costs, limitations, and patient-appropriateness.
• 1 mark — CVD: compares mechanism of statins and CABG; states when each is appropriate (statins universal + ongoing; CABG for severe multi-vessel).
• 1 mark — CVD: compares cost and accessibility of statins vs CABG using specific data from the table.
• 1 mark — T2D: compares lifestyle management and metformin on effectiveness and mechanism; states when each is appropriate.
• 1 mark — T2D: compares cost and patient-specific feasibility (socioeconomic barriers for lifestyle; near-universal PBS access for metformin).
• 1 mark — Uses specific numerical data from the stimulus table to support at least two claims.
• 1 mark — Reaches a coherent overall judgement explaining why biological effectiveness alone does not determine appropriateness (references access, adherence, patient context).
• 1 mark — Uses precise lesson terminology throughout (HMG-CoA reductase, AMPK, gluconeogenesis, GLUT4, PBS, HbA1c, visceral fat or equivalent).

Q2 — Sample Band 6 response (6 marks)

The claim is significantly overstated and contains three factual inaccuracies, though it correctly identifies gene therapy as a promising emerging field. [1 — overall evaluative judgement]

What is defensible: Gene therapy — both gene replacement using viral vectors (e.g. AAV) and genome editing using CRISPR-Cas9 — is a genuinely promising approach to treating genetic diseases. Research on CFTR gene delivery to lung epithelial cells in cystic fibrosis, and CRISPR editing for haematological conditions (sickle cell disease, beta-thalassaemia), has shown encouraging early clinical trial results. It is reasonable to describe gene therapy as a transformative future direction for medicine. [1 — correctly identifies defensible element]

What is inaccurate:

• "Already replacing pharmacological treatments": This is false. No gene therapy has replaced statins or metformin in clinical practice. Gene therapy for most non-infectious diseases remains experimental and has not been approved as a standard clinical treatment in Australia. The lesson specifically notes that CF gene therapy is "in early clinical trials" — not approved treatment. [1 — refutes "already replacing"]
• "Scientists have corrected cystic fibrosis using CRISPR-Cas9 in patients": This overstates current evidence. CRISPR-based CF correction has been demonstrated in cell cultures and animal models but has not been confirmed in approved human clinical practice. Lumacaftor/ivacaftor and related CFTR modulators are actually the current approved pharmacological treatment for CF, not gene therapy. [1 — refutes "corrected CF in patients"]
• "Statins and metformin are becoming obsolete": This is incorrect. Statins and metformin have extensive long-term evidence bases (decades of large randomised controlled trials), known safety profiles, very low cost through the PBS, and are accessible to virtually all Australians through GP prescription. Even if gene therapy is eventually approved for CVD or T2D, it would need to demonstrate equivalent or superior long-term effectiveness, safety, durability, and cost-effectiveness before these established treatments could be replaced. [1 — refutes "obsolete"]

Accurate reformulation: "Gene therapy, including CRISPR-Cas9 genome editing and viral vector-mediated gene delivery, is an emerging experimental treatment approach that has shown early promise in clinical trials for some genetic diseases (such as haematological conditions). For most non-infectious diseases — including CVD, Type 2 diabetes, and cystic fibrosis — gene therapy remains in experimental stages and is not yet approved as standard clinical treatment. Pharmacological treatments such as statins and metformin remain the evidence-based standard of care, with proven effectiveness, established safety profiles, and high accessibility through PBS subsidy." [1 — biologically accurate reformulation using precise qualifiers]

Marking criteria.

• 1 mark — States an overall evaluative judgement (e.g. "significantly overstated and contains factual inaccuracies").
• 1 mark — Identifies the defensible element (gene therapy is genuinely promising in early clinical trials for some genetic conditions).
• 1 mark — Correctly refutes "already replacing" — gene therapy for most non-infectious diseases is experimental, not in standard clinical practice.
• 1 mark — Correctly refutes or qualifies the CF/CRISPR claim — current approved CF treatment is pharmacological (CFTR modulators), not gene therapy; CRISPR correction has not been confirmed in approved human clinical treatment.
• 1 mark — Correctly refutes "statins/metformin obsolete" — both have decades of evidence, low PBS cost, and high accessibility; gene therapy would need to match these before replacement is defensible.
• 1 mark — Provides a biologically accurate reformulation using precise qualifiers (experimental, clinical trials, not yet approved as standard treatment) and correctly characterises the comparative status of pharmacological vs gene therapy.