L1 - Clinical Decision Making for Pharmacists

Overview of Clinical Decision Making

• Definition: everyday decision processes applied in a healthcare context, integrating evidence, experience, patient factors, and iterative review.
• Loop structure: information gathering → hypothesis → testing/evidence → reasoning → judgment → action → re-evaluation.
• Central aim: patient-centred, ethically sound, evidence-based, and collaborative care.

Stages of Clinical Decision Making

• Although cyclical and inter-dependent, clinically useful to discuss as discrete phases.

1. Screening (Early Detection & Prevention)

• Purpose: identify risk factors, red flags, or sub-clinical disease to trigger the decision cycle.
• Common pharmacist-linked examples:
  • Cardiovascular risk calculators (enter demographics, lipids, BP, etc.).
  • Diabetes: OGTT at 24\text{–}26 weeks gestation; high-risk Aboriginal & Torres Strait Islander screening.
  • Cancer: mammogram for women 50\text{–}74 y; cervical screening tests.
  • Routine labs: glucose, lipid profile, LFTs, eGFR, TSH.
• Information synthesis: align numeric results with guideline cut-offs (low, moderate, high risk), weigh benefits vs harms of pre-emptive therapy or lifestyle first.
• Shared decision: patient preference may override pharmacologic prophylaxis (e.g., refusal of statin despite high risk).

2. Diagnosis

• High-stakes choice; errors cascade into inappropriate therapy.
• Components:
  • Structured clinical assessment (signs/symptoms, e.g., pain score, PHQ-9 for depression).
  • Laboratory confirmation: HbA1c, INR, lipids.
  • Microbiology: urine culture, blood cultures, pathogen ID + susceptibility (integral to antimicrobial stewardship).
  • Point-of-care testing (POCT): bedside glucose, cholesterol; emerging saliva-based TDM.
  • Imaging: CXR for pneumonia, DEXA for osteoporosis.
• Pharmacist input: ensure right test ordered, interpret drug-induced abnormalities, flag antimicrobial resistance data.

3. Treatment Selection

• Influencers:
  • Local/national clinical guidelines & formularies.
  • Drug availability/registration; special access schemes for non-PBS medicines.
  • Lab data (e.g., susceptibilities) and patient factors (organ function, adherence likelihood, dosage form preference).
  • Economic/value-based care: \$40 branded vs \$1 generic where outcomes comparable.
  • Multidisciplinary consults (ID, oncology, pharmacy) for complex regimens, IV compatibility, interactions.
• Pharmacist actions: first-line choice, dose optimisation, TDM planning, patient counselling.

4. Monitoring & Follow-Up

• Determines whether the previous decisions were correct.
• Efficacy markers: BP reduction, glucose control, tumour shrinkage.
• Toxicity/organ markers: serum creatinine for AKI, ALT/AST for hepatotoxicity, neutrophils for myelosuppression.
• Therapeutic Drug Monitoring (TDM):
  • Measures blood/urine/saliva levels; compute exposure AUC = \int_{0}^{\tau} C(t)\,dt.
  • Bayesian software predicts dose–exposure using patient covariates to hit target range faster (vancomycin shift from trough-based to AUC/MIC-based dosing).
• Adherence surveillance: refill intervals, inhaler technique checks, DAA services.
• Referral pathways: medication reviews (HMR/RMMR), allied health, specialists.

Pharmacist’s Roles & Responsibilities Across Stages

• Guided by Australian Pharmacy Council Performance Outcomes.
• Key accountabilities:
  • Personal responsibility & documentation (PDL insured but must record interventions transparently).
  • Evidence-based, ethical decisions; weigh benefits/harms for individual context.
  • Shared decision making—provide balanced information, respect cultural/language needs (interpreters, Aboriginal Health Services).
  • Collaborative practice—liaise with prescribers, nurses, pathologists, allied health; flag interactions, contraindications, IV compatibility.
  • Expanded scope: vaccination, prescribing pilots, travel health, wound care clinics, chronic disease programs.

Models & Frameworks of Clinical Decision Making

• Hypothetico-Deductive: generate differential, test, rule-in/out; mirrors pharmacist drug-related-problem reasoning.
• Evidence-Based Model: strength & quantity of research guide choices; hierarchy to be covered in next lecture.
• Intuitive/Experience-Based: case reports paramount in rare diseases where RCT data absent.
• Shared Decision Making Model: clinician evidence + patient preferences → joint plan.

Decision Support Tools & Technology

• Clinical guidelines, PBS, local antibiograms.
• POCT devices expanding into TDM & diagnostics—faster turnaround enhances real-time decisions.
• Bayesian dosing platforms (e.g., InsightRx, DoseMeRx):
  • Input: weight, age, CrCl, prior levels.
  • Output: predicted AUC curve, recommended next dose.
  • Improves time to target, reduces nephrotoxicity.
• Patient decision aids (visual risk–benefit graphics, homework sheets) improve understanding and engagement.
• Developing bespoke frameworks: example paediatric nephrology genomic-testing tool created via literature review → ethnographic observation → stakeholder consensus.

Factors Influencing Decisions

• Patient: comorbidities, culture, literacy, willingness, adherence capacity.
• Drug: efficacy, toxicity profile, formulation size/route, cost.
• Professional: pharmacist capability, motivation, training in new tools.
• System/Organisation: assay availability, funding, regulatory approvals, workflow, multidisciplinary support.
• Evidence landscape: sometimes only low-level data exist.

Shared Decision Making in Practice

• Steps:
  1. Present all evidence-based options (including watchful waiting/lifestyle).
  2. Discuss pros/cons quantitatively where possible (use NNT, NNH, visual aids).
  3. Explore patient values/preferences.
  4. Agree on plan; document.
  5. Arrange follow-up & revise as needed.
• Benefits: ethical, empowers patients, increases adherence.
• Challenges: time, health literacy, clinician skill, resource constraints.
• Mitigation: visual tools (e.g., smiley-face antibiotic ear-infection diagram), interpreters, staged discussions.

Expanded Opportunities & Value-Based Care

• Pharmacists now engaged in cost-conscious prescribing advice; advocate generics when equivalent.
• Services searchable via “Find a Pharmacy” directories—illustrates growth in specialised pharmacist clinics.
• Importance of relationship-building with local GPs to position pharmacist as collaborator, not competitor, especially with incoming prescribing authority.

Key Takeaways & Exam Triggers

• Remember the four key stages (Screen → Diagnose → Treat → Monitor) and be able to state pharmacist duties in each.
• Cite concrete examples (e.g., OGTT timing, mammogram age range, AUC dosing for vancomycin).
• Describe at least three decision-making models and when each predominates.
• Explain Bayesian TDM rationale and give formula for AUC.
• Outline benefits & steps of shared decision making and provide a visual-aid example.
• List system-level factors that can hinder good decisions (drug access, assay delays).
• Link professional competence to capability–opportunity–motivation framework.