The metabolic syndrome: pathophysiology, clinical relevance, and use of niacin.

OBJECTIVE: To review the pathophysiology and clinical relevance for using niacin to treat the metabolic syndrome.

DATA SOURCES: Primary articles were identified through a MEDLINE search (1966-January 2003), and recommendations for treatment were obtained from the National Cholesterol Education Program Adult Treatment Panel (NCEP-ATP) III guidelines.

STUDY SELECTION AND DATA EXTRACTION: Published studies showing the effects of the metabolic syndrome, atherogenic dyslipidemia, and niacin were evaluated and reviewed.

DATA SYNTHESIS: The metabolic syndrome is a highly prevalent condition that affects 24% of American adults and significantly increases the risk of coronary heart disease (CHD). Most patients with metabolic syndrome have atherogenic dyslipidemia characterized by elevated triglycerides, low high-density-lipoprotein cholesterol (HDL-C), and small, dense low-density-lipoprotein cholesterol (LDL-C) particles. The NCEP-ATP III identifies patients with the metabolic syndrome as candidates for intensified therapy. Lifestyle modifications and drug therapy are recommended. Niacin represents a good option for treating the triad of lipid abnormalities seen in the metabolic syndrome because it raises HDL-C, lowers triglycerides, and increases LDL-C particle size.

CONCLUSIONS: Treatment of the metabolic syndrome is recommended by NCEP-ATP III to further reduce CHD risk after the LDL-C target has been met. Prospective clinical studies are needed to define the impact of niacin and other lipid-modifying agents on CHD morbidity and mortality in patients with the metabolic syndrome.