Written by Marcia J. Egles, MD.
Cholesterol is essential to the human body. It is a structural part of the cell membrane of every cell. Unfortunately in levels too high, as occurs in over 100 million Americans, cholesterol can be dangerous. Excess cholesterol can pile up within the walls of blood vessels, narrowing their diameters. Heart attacks and strokes can result. High cholesterol is largely preventable and treatable through diet, exercise and medications.
The use of statin therapy to reduce levels of low-density lipoprotein (LDL) cholesterol in high risk patients results in a 30 to 40% reduction in the rate of heart attack and other serious events(1). Additional therapeutic interventions are being sought for those at especially high risk. One approach has involved the addition of the drug ezetimide which helps block cholesterol absorption. A second approach is to bolster the levels of HDL ( commonly called “good cholesterol”) by the addition of niacin to statin therapy. The recent study of such patients on statin therapy reported a clear superiority of the effectiveness of niacin over ezetimide (2).
The study enrolled 363 adults (average age 65) who had been receiving long-term statin therapy for high cholesterol and heart disease. Eighty per cent of the patients were male. All the patients had been receiving chronic statin treatment ( atorvastatin or simvastatin in 95% of patients) for one to eleven years prior to the study. The patients were randomly assigned to receive, in addition to their regular statin treatment, either extended release niacin (advanced to 2000mg/day) or ezetimibe (10mg/day). The measurement to determine the effectiveness of the treatment was the wall thickness of the common carotid artery in the neck. The wall thickness was determined by ultrasound examination. The study compared the differences between the two groups with regard to the change of arterial wall thickness after 14 months of treatment.
As compared with ezetimide, niacin had a greater efficacy. No significant differences in the carotid wall thickness were seen with the ezetimide group after treatment. Reductions of 0.014 millimeter thickness on average at 14 months were seen in the niacin group (p value equal to 0.003). The researchers considered this result to be so statistically definitive for niacin’s effectiveness that the study was halted early after 208 patients completed the 14 months. The incidence of major cardiovascular events was also lower in the niacin group at 1% versus 5% in the ezetimide group (p value equal to 0.04). Sixteen of the 176 (9%)patients in the ezetimide group left the study – nine withdrew and seven died. In the niacin group, 28 of 187 (15%) left with 27 who withdrew and one who died. Adverse drug effects such as skin flushing were cited as the reason for withdrawal in 17 of the 27 in the niacin group.
Abstractor’s note: The B-vitamin niacin has been used clinically for more than fifty years with low cost and an excellent safety record. The unpleasant side-effect of skin flushing usually is quite temporary, and often does not recur beyond two weeks of daily treatment. Pre-treatment with aspirin or ibuprofen can prevent the flushing. The extended-release niacin used in this study was at a very high dosage (100 times the RDA) and prescribed by a physician.
Source: Taylor, Allen J., et al. “Extended-release niacin or ezetimibe and carotid intima–media thickness.” New England Journal of Medicine 361.22 (2009): 2113-2122.
© 2009 Massachusetts Medical Society.
Posted January 18, 2010.
References:
- LaRosa JC, He J, Vupputuri S. Effect of statins on risk of coronary disease: a meta-analysis of randomized controlled trials. JAMA 1999;282:2340-2346.
- Taylor AJ,VillinesTC, Stanek EJ,et al. Extended-release niacin or ezetimibe and carotid intima-media thickness. N Engl J Med 2009;361:2113-2122.
