Effects of niacin on the incidence of new onset diabetes and cardiovascular events in patients with normoglycaemia and impaired fasting glucose

Abstract

This post hoc analysis from the Coronary Drug Project (CDP) evaluated the effects of niacin vs. placebo on the incidence of new onset type 2 diabetes mellitus (T2DM) and cardiovascular event rates in patients with normal and impaired fasting glucose (IFG). The CDP was a randomised, placebo-controlled clinical trial of lipid-modifying agents in men with previous myocardial infarction. Normoglycaemia and IFG were defined as fasting plasma glucose (FPG) < 5.6 mmol/l and FPG ≥ 5.6 but < 7.0 mmol/l, respectively. New onset T2DM was defined by ≥ 1 of the following: clinical diagnosis of T2DM, use of an antihyperglycaemic therapy, or two FPG values ≥ 7.0 mmol/l. The incidence of new onset T2DM was higher in patients with IFG (16.5%) compared with those with normoglycaemia (5.4%), and was slightly higher with niacin vs. placebo in both normoglycaemic (6.8% vs. 4.9%; p = 0.07) and IFG (19.8% vs. 15.2%; p = 0.05) patients. Consistent with previous analyses, the cardiovascular benefit of niacin was independent of baseline glycaemic status (normal, IFG, T2DM) and change in fasting glucose level from baseline to year 1. Despite a modest increase in risk of new onset T2DM with long-term niacin therapy, there is a potential cardiovascular benefit of niacin.