Effects of pravastatin in 3260 patients with unstable angina: results from the LIPID study

The LIPID study is a major trial of secondary prevention of coronary-heart-disease events that includes hospital admission with unstable angina (as well as myocardial infarction) as a qualifying event. In this substudy of LIPID, we compared subsequent cardiovascular risks and the effects of pravastatin in patients with previous unstable angina or previous myocardial infarction.

3260 patients diagnosed with unstable angina and 5754 with acute myocardial infarction 3-36 months previously were randomly assigned 40 mg pravastatin daily or placebo over a mean of 6.0 years. The risk reduction of a range of cardiovascular events was estimated by means of the hazard ratio in Cox's proportional hazards model.

Among patients assigned placebo, survival in the two diagnosis groups was similar. The relative risk reduction for mortality with pravastatin was 20.6% in the myocardial infarction group and 26.3% in the unstable angina group (p=0.55). Pravastatin significantly reduced the rates of all prespecified coronary endpoints in the myocardial infarction group. In patients with previous unstable angina, coronary heart disease mortality, total mortality, myocardial infarction, a need for coronary revascularisation, the number of admissions to hospital, and the number of days in hospital were significantly lower with pravastatin. Overall, hospital admission for unstable angina was the most common endpoint (24.6% of the placebo group; 22.3% of the pravastatin group).

Patients who have survived acute myocardial infarction or unstable angina have a similar long-term prognosis, a high occurrence of subsequent unstable angina, and benefit similarly from therapy with pravastatin.