Is niacin effective for primary or secondary prevention of cardiovascular or cerebrovascular events?
Prescription niacin (nicotinic acid, vitamin B3) does not reduce myocardial infarctions, strokes, or overall mortality when used for primary or secondary prevention.1 (Strength of Recommendation: A, based on consistent, good-quality patient-oriented evidence.)
Prescription niacin is one of the most effective agents in increasing serum levels of high-density lipoprotein (HDL) cholesterol.2 Previous research has shown that lower levels of HDL cholesterol are independently associated with an increased risk of cardiovascular disease (CVD), and that use of prescription niacin could raise HDL cholesterol levels and may reduce cardiovascular events.3,4 The objective of this review was to assess the effectiveness of niacin therapy (monotherapy or in addition to statin therapy) vs. placebo in terms of overall mortality, cardiovascular events, cerebrovascular events, and adverse effects.
This Cochrane review included 23 randomized controlled trials (published between 1968 and 2015) involving 39,195 participants.1 The authors looked for studies including patients who were considered at risk of CVD as well as those with known CVD. The primary outcome examined was overall mortality, as discussed in 12 high-quality studies. Niacin did not appear to lower overall mortality. Concurrent statin use, comorbidities, and duration of niacin treatment did not change the impact on the primary outcome. Niacin also had no apparent impact on the secondary outcomes of myocardial infarctions, strokes, or need for revascularization procedures.
Niacin did appear to increase the risk of several adverse effects, including flushing (relative risk [RR] = 7.69; 95% confidence interval [CI], 4.14 to 14.28; number needed to harm [NNH] = 3.5), pruritus (RR = 5.26; 95% CI, 2.68 to 10.32; NNH = 4.8), rash (RR = 3.15; 95% CI, 1.94 to 5.13; NNH = 77), and gastrointestinal symptoms (RR = 1.69; 95% CI, 1.37 to 2.07; NNH = 125). Niacin users were at risk of discontinuing the medication because of these adverse effects (RR = 2.17; 95% CI, 1.70 to 2.77; NNH = 8 [95% CI, 5 to 14]). Alarmingly, there was also an apparent increased risk of developing diabetes mellitus in patients who used niacin (RR = 1.32; 95% CI, 1.16 to 1.51; NNH = 143).
Although current guidelines mention that niacin is used to potentially lower the risk of CVD, it is only discussed insofar as to caution physicians regarding the adverse effects associated with its use.5 Based on this review, niacin should not be used for primary or secondary prevention of cardiovascular or cerebrovascular events.