Niacin for primary and secondary prevention of cardiovascular events.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 28616955 · doi:10.1002/14651858.CD009744.pub2
What was done
A Cochrane systematic review and random-effects meta-analysis of randomized controlled trials (RCTs) published between 1968 and 2015. Eligible trials evaluated niacin (monotherapy or combined with other therapies) versus placebo or usual care in adults with or without established cardiovascular disease (CVD), with at least 6 months of treatment. The review analyzed 23 RCTs comprising 39,195 participants (mean age 33 to 71 years; median treatment duration 11.5 months; median dose 2 g/day; background statin use 0% to 100%). Evidence quality was assessed using GRADE.
What was found
Niacin did not reduce: - All-cause mortality: RR 1.05 (95% CI 0.97 to 1.12; 12 trials, n = 35,543; I2 = 0%; high-quality evidence) - Cardiovascular mortality: RR 1.02 (95% CI 0.93 to 1.12; 5 trials, n = 32,966; I2 = 0%; moderate-quality evidence) - Non-cardiovascular mortality: RR 1.12 (95% CI 0.98 to 1.28; 5 trials, n = 32,966; I2 = 0%; high-quality evidence) - Fatal or non-fatal myocardial infarction: RR 0.93 (95% CI 0.87 to 1.00; 9 trials, n = 34,829; I2 = 0%; moderate-quality evidence) - Fatal or non-fatal stroke: RR 0.95 (95% CI 0.74 to 1.22; 7 trials, n = 33,661; I2 = 42%; low-quality evidence) Participants randomized to niacin were significantly more likely to discontinue treatment due to side effects than controls: RR 2.17 (95% CI 1.70 to 2.77; 17 trials, n = 33,539; I2 = 77%; moderate-quality evidence).
Why it matters
Despite improving lipid profiles, niacin does not reduce clinical cardiovascular events or mortality in primary or secondary prevention and more than doubles treatment discontinuation from adverse effects.
Limits
Included trials spanned nearly five decades with wide variation in background medical therapy (statin use 0% to 100%) and baseline risk (prior MI 0% to 100%). Substantial heterogeneity was observed for side-effect discontinuation (I2 = 77%) and stroke outcomes (I2 = 42%). Specific adverse effects were not reported in the abstract.
Cited by
- contradicts Regular flushing niacin provides massive benefits for increasing HDL cholesterol levels.