Does Vitamin E reduce the Number of Coronary Ischemic Episodes and Should We Use It inPractice
Appraiser: Eric W. Terman
Clinical Bottom Lines:
Date Appraised: July 18, 1997
Vitamin E >400 iu per day did significantly reduce the combined number of non-fatal MI's and cardiovascular death The actual reduction in risk was roughly 2.6%. The treatment was carried out for 510days (1.4 years). This means that 38 patients would need to be treated for 510d before one event was prevented
The study showed a greater reduction for non-fatal MI's, than for fatal cardiovascular events. If only nonfatal events are considered the risk reduction is 2.8% which means 35 would need to be treated.
The Evidence:
Double blind placebo RCT of 2002 patients with known CAD
| Outcomes 510 days | Placebo | Vitamin E | Odds Ratio Substitute Relative Risk Reduction (RRR) |
ARR | NNT |
| Major CV events | 62/967 0.0641 |
41/1035 0.0396 |
40% (0.0641-0.0396)/0.0641 |
2.6% | 38 |
| non-fatal MI | 41/967 0.0423 |
14/1035 0.0135 |
68% (0.0423-0.0135)/0.043 |
2.8% | 34 |
| fatal CV events | 23/967 0.0237 |
27/1035 0.0260 |
no reduction, also not significant | no benefit |
Comments:
1. The patient population all had known CAD so this can not be
extrapolated to the general
population.
2. There was not a significant reduction in fatal events when
comparing Vitamin E to placebo.
3. The Kaplan-Meier curves deviated for both major cardiovascular
events and non-fatal MI.
4. There is little harm so if a patient is interested it could be
helpful.
Reference:
Stephens NG, Parsons A, Schofield PM, et al. Randomised
controlled trial of vitamin E in patients with coronary disease:
Cambridge Heart Antioxidant Study (CHAOS). Lancet. 1996
March 23;347:781-6