Levels of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, and risk of coronary artery disease: A meta-analysis based on 4713 participants

Background Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase by competing with L-arginine. As a result, the expression of nitric oxide decreases and endothelial dysfunction occurs. Studies have evaluated the association between the serum ADMA level and risk of coronary artery disease. However, conflicting results have been obtained. Methods Pubmed, Web of Science, Embase, Ovid, Cochrane databases were searched to identify eligible studies published in English until December 2014. Association was assessed on the basis of weighted mean differences (WMD) with 95% confidence intervals (CIs). Publication bias was analysed using Begg's and Egger's tests. Sensitivity analysis was performed to evaluate result stability. Results A total of 16 case-control studies with 2939 patients and 1774 controls were included in the meta-analysis. Pooled result indicated that patients with coronary artery disease yielded a higher ADMA level than healthy controls (WMD: 0.248, 95% CI: 0.156-0.340; p=1.16 e-7). Sensitivity analysis suggested that our meta-analysis result was stable. Subgroup analysis found a similar pattern in patients with myocardial infarction (WMD: 0.397, 95% CI: 0.112-0.683; p=0.0106), stable angina pectoris (WMD: 0.197, 95% CI: 0.031-0.364; p=0.02) and unstable angina pectoris (WMD: 0.857, 95% CI: 0.293-1.420; p=0.003). Conclusions Meta-analysis results indicated that an increased ADMA level is associated with an increased risk of coronary artery disease.