Extended-Release Niacin Therapy and Risk of Ischemic Stroke in Patients With Cardiovascular Disease The Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides: Impact on Global Health Outcome (AIM-HIGH) Trial

Background and Purpose In Atherothrombosis Intervention in Metabolic Syndrome with low HDL/High Triglycerides: Impact on Global Health Outcomes (AIM-HIGH) trial, addition of extended-release niacin (ERN) to simvastatin in participants with established cardiovascular disease, low high-density lipoprotein cholesterol, and high triglycerides had no incremental benefit, despite increases in high-density lipoprotein cholesterol. Preliminary analysis based on incomplete end point adjudication suggested increased ischemic stroke risk among participants randomized to ERN. Methods This final analysis was conducted after complete AIM-HIGH event ascertainment to further explore potential relationship between niacin therapy and ischemic stroke risk. Results There was no group difference in trial primary composite end point at a mean 36-month follow-up among 3414 patients (85% men; mean age, 649 years) randomized to simvastatin plus ERN (1500-2000 mg/d) versus simvastatin plus matching placebo. In the intention-to-treat analysis, there were 50 fatal or nonfatal ischemic strokes: 18 (1.06%) in placebo arm versus 32 (1.86%) in ERN arm (hazard ratio [HR], 1.78 [95% confidence interval {CI}, 1.00-3.17; P=0.050). Multivariate analysis showed independent associations between ischemic stroke risk and >65 years of age (HR, 3.58; 95% CI, 1.82-7.05; P=0.0002), history of stroke/transient ischemic attack/carotid disease (HR, 2.18; 95% CI, 1.23-3.88; P=0.0079), elevated baseline Lp(a) (HR, 2.80; 95% CI, 1.25-6.27 comparing the middle with the lowest tertile; HR, 2.31; 95% CI, 1.002-5.30 comparing the highest with the lowest tertile; overall P=0.042) but a nonsignificant association with ERN (HR, 1.74; 95% CI, 0.97-3.11; P=0.063). Conclusions Although there were numerically more ischemic strokes with addition of ERN to simvastatin that reached nominal significance, the number was small, and multivariable analysis accounting for known risk factors did not support a significant association between niacin and ischemic stroke risk. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00120289.