📚 Part of the Cardiovascular Landmark Trials guide — every landmark trial in one place.
Series: Landmark Trials in Endocrinology & Metabolism | Study #30
Category: Lipids & Statins · Cardiovascular Primary Prevention | Design: Multicentre, double-blind, placebo-controlled RCT | n: 6,595 | Follow-up: 4.9 years (mean)
📋 Summary
Authors: Shepherd J et al., for the West of Scotland Coronary Prevention Study Group
Journal: N Engl J Med 1995;333:1301–1307 | DOI: 10.1056/NEJM199511163332001
WOSCOPS enrolled 6,595 men aged 45 to 64 years with hypercholesterolaemia (mean plasma cholesterol 272 ± 23 mg/dL; 7.0 ± 0.6 mmol/L) and no history of myocardial infarction, randomly assigned to pravastatin 40 mg each evening or placebo for an average of 4.9 years. The primary endpoint was the combined incidence of nonfatal MI and death from coronary heart disease. Pravastatin lowered plasma cholesterol by 20% and LDL-cholesterol by 26%. The primary endpoint occurred in 248 patients in the placebo group and 174 in the pravastatin group (31% relative risk reduction; 95% CI 17 to 43%; p<0.001). Definite nonfatal MI was reduced by 31% (p<0.001), death from coronary heart disease by 33% (p=0.042 for definite plus suspected cases), and death from all cardiovascular causes by 32% (p=0.033). All-cause mortality was reduced by 22% (95% CI 0 to 40%; p=0.051), a result that narrowly missed conventional significance but was consistent with a meaningful mortality benefit. No excess of non-cardiovascular deaths was observed. This was the first large randomised trial to demonstrate that statin therapy reduces coronary events in men without prior MI — establishing the primary prevention indication for statins.
📊 Key Findings
| Outcome | Pravastatin | Placebo | Effect Size |
|---|---|---|---|
| Nonfatal MI or coronary death (primary) | 174 | 248 | 31% RRR (17–43%) · p<0.001 |
| Definite nonfatal MI | — | — | 31% reduction · p<0.001 |
| CV death (all causes) | — | — | 32% reduction · p=0.033 |
| All-cause mortality | — | — | 22% reduction (0–40%) · p=0.051 |
| LDL-cholesterol change | −26% | — | Achieved with pravastatin 40 mg |
| Non-CV deaths | — | — | No excess |
WOSCOPS
RCT · primary prevention · 4.9 yr
Pravastatin cut nonfatal MI or coronary death by 31% in men with hypercholesterolaemia and no prior MI, establishing the primary prevention indication for statins.
💬 Expert Commentary
WOSCOPS and 4S were published within one year of each other and together defined the two major statin use contexts that have shaped lipid management guidelines ever since. While 4S established the secondary prevention indication with a landmark mortality result, WOSCOPS was the first primary prevention trial to demonstrate that statin therapy reduces coronary events in patients who have not yet had a MI. The populations differ fundamentally: 4S enrolled patients with established coronary disease and relatively high event rates, while WOSCOPS enrolled men with elevated cholesterol and no prior MI, in whom the event rate over 4.9 years was lower (6.0 events per 100 person-years in the placebo group), producing a NNT of approximately 40 per coronary event prevented over 4.9 years compared with the NNT of around 12 for coronary events in 4S.
WOSCOPS answered a question with direct policy implications: should statins be used only after a cardiovascular event has occurred, or should they be initiated in high-risk individuals to prevent the first event? The clear reduction in coronary events and the trend towards all-cause mortality reduction (p=0.051) provided sufficient evidence for regulatory approval of pravastatin for primary prevention in hypercholesterolaemic men at elevated risk. However, WOSCOPS enrolled only men, and a comparable primary prevention trial in women was not conducted until the JUPITER trial (rosuvastatin in patients with elevated hsCRP but normal LDL), which reported in 2008. WOSCOPS also had a more specific entry criterion than subsequent primary prevention trials — moderate to severe hypercholesterolaemia — and the question of whether statin therapy benefits primary prevention in individuals with lower baseline LDL was addressed by HPS (Study #31), which enrolled patients with a lower cholesterol threshold and demonstrated benefit regardless of baseline LDL level.
Limitations: The trial enrolled only men, limiting generalisability to women. The near-miss all-cause mortality result (p=0.051) suggests the trial was modestly underpowered for mortality. The enrolled population had moderate to severe hypercholesterolaemia, and findings cannot be directly extrapolated to lower-risk primary prevention patients. The study was funded by Bristol-Myers Squibb.
🔑 BOTTOM LINE
WOSCOPS demonstrated that pravastatin reduces the combined incidence of nonfatal MI and coronary death by 31% in men with hypercholesterolaemia and no prior MI, establishing the primary prevention indication for statin therapy and laying the evidence base for broad population-level lipid management programmes in high-risk individuals without established cardiovascular disease.
⭐ Clinical Impact Rating: ●●●●● Practice-defining