MI-reduction of average cholesterol levels decreases repeat MI and death

Clinical Scenario: 65 yr old woman with average LDL post MI

Three-part Question: Does lowering cholesterol in a patient with CAD and average cholesterol levels decrease the risk of MI and death?

Search Terms: cholesterol reduction and MI using MEDLINE

The Study:
Double-blinded concealed randomised controlled trial with intention-to-treat. Men and postmenopausal women were eligible if they had an acute MI btw 3 and 20 months before randomisation, 21-75 yrs of age, total cholesterol <240 mg/dl, LDL 115-174 mg/dl, fasting TG <350 mg/dl, fasting glucose <220 mg/dl, LVEF> 25%, no symptomatic CHF.
Control group (N = 2078; 2078 analysed): dietary therapy and cholestyramine if LDL remained >175
Experimental group (N = 2081; 2081 analysed): pravastatin 40 mg od and dietary therapy and cholestyramine if LDL remained >175

The Evidence:

Outcome	Time to Outcome	CER	EER	RRR	ARR	NNT
death from CAD or nonfatal MI	median 5 yrs	0.132	0.10	24%	0.032	31
	95% Confidence Intervals:			10% to 39%	0.013 to 0.051	19 to 80
stroke	median 5 yrs	0.038	0.03	21%	0.008	125
	95% Confidence Intervals:			-8% to 50%	-0.003 to 0.019	NNT = 53 to INF; NNH = 332 to INF
overall mortality	median 5 yrs	0.094	0.09	4%	0.004	250
	95% Confidence Intervals:			-14% to 23%	-0.014 to 0.022	NNT = 46 to INF; NNH = 74 to INF

Comments:

1. LDL was 28% lower in treatment group than placebo group
2. effect of pravastatin was greater among women than among men
3. age of pt not a factor in effectiveness of pravastatin
4. reduction in coronary events influeneced by pretreatment level of LDL, higher the value, the greater the risk reduction
5. risk of breast cancer increased in pravastatin group-1 pt in placebo and 12 in pravastatin group

Expiry date: August 1998

Reference:

1. Sacks FM et al. The effects of pravastatin on coronary events after MI in patients with average cholesterol levels. NEJM 1996;335:1001-9.

Click here to comment on this CAT