Extended-Release Niacin Safe, Effective in Type 2 Diabetes

Laurie Barclay, MD

July 26, 2002

July 26, 2002 -- Although niacin has long been relatively contraindicated in type 2 diabetes due to its adverse effects on glucose control, a report in the July 22 issue of the Archives of Internal Medicine suggests that once-daily extended release niacin was well tolerated and effective for improving lipid levels in type 2 diabetics. However, the higher dose did significantly worsen glycemic control compared with placebo.

"Extended-release niacin may be considered as therapy in combination with statins, or in some cases, without statins, in the management of dyslipidemia associated with type 2 diabetes," write Scott M. Grundy, MD, PhD, of the University of Texas Southwestern Medical Center in Dallas, and colleagues from the Diabetes Multicenter Research Group.

In this double-blind, placebo-controlled trial, 148 patients with type 2 diabetes were randomized to treatment with 1,000 mg per day extended-release (ER) niacin, 1,500 mg per day ER niacin, or placebo. Subjects were allowed to continue medications used to treat underlying conditions; 47% were receiving statins, and 81% took drugs for diabetes control.

Mean high-density lipoprotein cholesterol (HDL-C) levels were essentially unchanged in the placebo group, increased by 13% to 19% in the group taking 1,000 mg ER niacin, and increased by 22% to 24% in the group taking 1,500 mg ER niacin ( P<.05). Triglyceride (TG) levels decreased by 5% to 8% in the placebo group, by 15% to 20% in the 1,000 mg ER niacin group, and by 28% to 36% in the 1,500 mg group.

At 16 weeks, low-density lipoprotein cholesterol (LDL-C) levels were 9% higher in the placebo group, 5% higher in the 1,000 mg ER niacin group, and 7% lower in the 1,500 mg group. Mean total cholesterol levels increased by 4% in the placebo and 1,000 mg ER niacin groups and decreased by 6% in the 1,500 mg ER niacin group.

Subjects in the 1,000 mg ER niacin group had higher body mass indexes, which the authors suggest may have dampened the triglyceride-lowering effect of niacin.

Glycated hemoglobin levels at baseline and at week 16 were 7.13% and 7.11% in the placebo group, 7.28% and 7.35% in the 1,000 mg group ( P=.16 vs. placebo), and 7.2% and 7.5% in the 1,500 mg group ( P=.048 vs. placebo). Four patients withdrew from the study because of inadequate glycemic control.

In a telephone interview with Medscape Cardiology, Grundy noted that low HDL and high triglyceride levels are particularly problematic in diabetic patients. Grundy was chairman of the Third Adult Treatment Panel (ATP III), which recently published guidelines that establish recommended approaches for the hypercholesterolemic patient.

Grundy said that treatment of the dyslipidemias may become analogous to the current approach to antihypertensive treatment, in which the push to ever higher doses of monotherapy is being replaced with combination agents that incorporate multidrug regimens into a single prescription. The future of optimal lipid management may follow the same path, Grundy said, using low-dose combinations of proven anticholesterolemic agents, instead of prescribing ever-higher doses of statins. At the present time, the most likely complement would be niacin, especially in a time-release formulation, and therefore the present results, showing that low-dose niacin is safe and useful in diabetic patients, are particularly interesting.

Kos Pharmaceuticals in Miami, Florida, supported this study.

Additional reporting by David Good, editor of Medscape Cardiology.

Arch Intern Med. 2002;162:1568-1576

Reviewed by Gary D. Vogin, MD


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