Niacin, also known as nicotinic acid, vitamin PP or Vitamin B3, formula C6H5NO2, is an organic compound. It is used to raise HDL cholesterol levels (good cholesterol), as well as reducing triglyceride levels.
A considerable number of patients are at significant risk of cardiac death, stroke or heart attack, despite having well controlled cholesterol - when their LDL cholesterol has reached 30-80mg/dL, known as 'therapeutic levels' as a result of statin therapy.
Some researchers and experts have said that this higher risk might be because there is not enough good cholesterol, and triglyceride levels may be too high. High triglyceride levels are linked to greater cardiovascular risk, especially among patients whose LDL is high and HDL is low.
The study - Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health (AIM-HIGH) - was led by William E. Boden, M.D., professor of medicine and public health at the University at Buffalo in New York.
Patients were randomly selected into two groups:
- Intervention group - 1,718 individuals received 1,500 to 2,000 mg/day, extended-release niacin
- Control group - 1,696 participants received placebo
LDL cholesterol (bad cholesterol) levels in the intervention group dropped by about 12%.
Despite better results, the risk of heart attack, stroke or heart-related deaths did not change in the intervention group, the researchers explained. Neither did the risk of being admitted to hospital.
- Intervention group - 16.4% had a heart attack, stroke, heart-related death, or hospitalization
- Placebo group - 16.2% had a heart attack, stroke, heart-related death, or hospitalization
The trial was stopped 18 months early because of a clear lack of benefit.
Dr. Boden said:
"If you are a patient with stable cardiovascular disease who has achieved and maintained very low levels of LDL cholesterol on a statin, these research findings indicate the addition of high-dose niacin does not improve your risk for future events and is therefore not needed."
Boden stressed that their study focused only on patients who achieve very low LDL levels - about 20% of patients with heart disease.
"At this point, we don't know whether HDL-raising would be beneficial for the other 80 percent of patients who are unable to lower their LDL this much."
Co-principle investigator, Jeffrey Probstfield, M.D., professor of medicine and cardiology at the University of Washington in Seattle, said:
"Also, by including only stable patients, AIM-HIGH didn't address the possible benefit of niacin therapy in patients who have experienced a recent heart attack or heart-related chest pain. Thus, it remains unclear whether such higher-risk patients with low HDL levels may benefit from niacin or other drugs which raise HDL levels."