Dyslipidaemia — KFP-style written assessment

KFP 1 (10 marks)

A 55-year-old woman has an absolute five-year CVD risk placing her in the 'high benefit' category for statin therapy. Her LDL cholesterol is 3.4 mmol/L. She read online that statins are 'over-prescribed in healthy people'. ^{[1] [2]}

1. What do the CTT meta-analyses show per 1 mmol/L LDL reduction, and how does that address her concern? (4) ^[1]
2. What does the low-risk subgroup analysis add? (3) ^[2]
3. Which primary-prevention trials established this territory before CTT? (3) ^{[6] [7]}

Model answers

1. The combined CTT analysis found major vascular events fell to RR 0.78 (95% CI 0.76-0.80) per 1 mmol/L LDL reduction across all patient types; more intensive regimens added a further 15% reduction versus standard ones. Her concern is answered with proportional-benefit arithmetic rather than opinion. ^[1]
2. CTT's individual-participant analysis stratified patients into five baseline risk categories: the proportional event reduction was at least as big in the two lowest-risk categories (RR 0.62 and 0.69) as higher ones — the 'healthy people don't benefit' argument fails on trial data. ^[2]
3. WOSCOPS: pravastatin reduced definite coronary events by 31% in hypercholesterolaemic men without prior MI. ASCOT-LLA: atorvastatin 10 mg cut primary events by 36% (HR 0.64) within the first year in hypertensive patients with average-or-lower cholesterol. ^{[7] [6]}