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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Effect of niacin therapy on cardiovascular outcomes in patients with coronary artery disease.

JK Duggal, M Singh, N Attri, PP Singh, N Ahmed, S Pahwa, J Molnar, S Singh, S Khosla, and R Arora.

Review published: 2010.

Link to full article: [Journal publisher]

CRD summary

This review concluded that niacin therapy was associated with a statistically significant reduction the risk of cardiovascular events in patients with coronary artery disease, but the small decrease in coronary and cardiovascular mortality was not statistically significant. As most of the data came from older trials (1975 to 1990) that may not be as relevant to current practice, the authors' conclusions should be treated with caution.

Authors' objectives

To evaluate the effect of niacin on cardiovascular outcomes in patients with coronary artery disease.

Searching

PubMed, EMBASE, CINAHL and the Cochrane Library were searched to January 2009 for published English language studies. Search terms were reported. 'Related links' to relevant articles and reference lists of retrieved papers were checked.

Study selection

Randomised controlled trials (RCTs) that assessed the use of niacin in patients with a history of myocardial infarction or evidence of coronary artery disease, compared with placebo or control, were eligible for inclusion. Eligible trials were required to have a follow up of 12 months or longer. Niacin could be used as a primary or adjunct therapy.

Eligible studies had to report at least one of the following outcomes: all-cause mortality, non-fatal myocardial infarction, coronary artery revascularisation or stroke/transient ischaemic event. Cardiac and cardiovascular mortality were also reported.

In the included trials, the age of patients ranged from 30 to 76 years; most were men. Diagnoses were varied: history of myocardial infarction; angiographic evidence of atherosclerosis or coronary artery bypass graft; history of cardiovascular disease; and angiographically evident coronary artery disease or coronary stenosis. Dosing regimes ranged from 0.125 to 12g daily.

The authors did not state how the papers were selected for the review.

Assessment of study quality

Quality was assessed based on adequacy of concealment of randomisation treatment sequence and completeness of follow-up.

The authors did not state how many reviewers performed the validity assessment.

Data extraction

Two reviewers independently extracted data to calculate relative risk (RR) and 95% confidence intervals (CIs) for outcomes for each trial. Disagreements were resolved by consensus.

Methods of synthesis

Pooled relative risks and 95% confidence intervals were calculated using Mantel-Haenszel fixed-effect model.

Heterogeneity was assessed using the Cochran Q statistic.

Results of the review

Seven RCTs (5137 participants) were included. One trial (published in 1975) had 3,908 participants; numbers in the others trials (published 1987 to 2005) ranged from 76 to 555 participants. All trials reported adequate concealment of allocation. Follow-up ranged from one to eight years and was more that 90% complete.

Ischaemic events: Compared with placebo, niacin reduced the risk of coronary artery revascularisation (RR 0.307, 95% CI 0.150 to 0.628; I2=0%; five trials), non-fatal myocardial infarction (RR 0.719, 95%CI 0.603 to 0.856; I2=0%; five trials) and stroke or transient ischaemic event (RR 0.759, 95%CI 0.613 to 0.940; I2=0%; five trials).

Mortality: There was no statistically significant difference between placebo and niacin therapy for cardiac mortality, cardiovascular mortality and all-cause mortality.

There was no evidence of statistical heterogeneity.

Authors' conclusions

In secondary prevention of coronary artery disease, niacin was associated with a statistically significant reduction in cardiovascular events, and a small, non-statistically significant decrease in coronary and cardiovascular mortality.

CRD commentary

The aims of the review were clearly stated for participants, treatment, study design and outcomes. The search covered a number of sources, but was limited to English language; it was possible that language bias or publication bias may have affected the review. The methods of data extraction were those aimed at reducing reviewer error or bias, but methods for study selection and quality assessment were unclear.

Quality assessment of included trials was limited. Given the lack of significant heterogeneity between trials, the methods of synthesis appeared appropriate. However, the authors gave little information about differences between trials, in particular any adjunctive drug therapies, or whether comparators in the individual trials were controls or placebo. Details of the participants were also limited; this could affect the generalisability of the results. There was no mention of the assessment of any possible adverse effects. There were discrepancies between some of the numbers in tables and text.

Most of the data came from three older trials (1975 and 1990). Drug regimes and lifestyles have changed over time, in particular with the use of statins, and results may not now be as relevant to current practice. The authors' conclusions should be treated with caution.

Implications of the review for practice and research

Practice: the authors did not state any implications for practice.

Research: the authors stated that a large-scale trial of niacin, used in the era of statin therapy, is needed to assess the effects on clinical endpoints.

Funding

None.

Bibliographic details

Duggal JK, Singh M, Attri N, Singh PP, Ahmed N, Pahwa S, Molnar J, Singh S, Khosla S, Arora R. Effect of niacin therapy on cardiovascular outcomes in patients with coronary artery disease. Journal of Cardiovascular Pharmacology and Therapeutics 2010; 15(2): 158-166. [PubMed: 20208032]

Indexing Status

Subject indexing assigned by NLM

MeSH

Cardiovascular Diseases /mortality /prevention & control; Coronary Artery Disease /drug therapy /mortality /prevention & control; Humans; Hypolipidemic Agents /therapeutic use; Myocardial Infarction /mortality /prevention & control; Myocardial Revascularization /statistics & numerical data; Niacin /therapeutic use; Randomized Controlled Trials as Topic

AccessionNumber

12010004154

Database entry date

16/03/2011

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 20208032

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