Munir, Muhammad S.

Background The association between the 9p21-3 locus and coronary heart disease (CHD) is well known. We performed a systematic review of the literature to assess whether this locus was associated with severity of coronary atherosclerosis. Data Sources Multiple relevant electronic databases were searched through September 2012 for English language studies with comparative design. Data extraction We tested the association of the 9p21-3 locus: 1) measures of severity of coronary atherosclerosis [number of diseased vessels, Gensini Score, Duke CHD Prognostic Index (Dc.PI)]. 2) angiographic outcomes [change in minimum lumen diameter ([[Unable to Display Character: ∆]]MLD) and number of new lesions at follow-up] and 3) key clinical outcomes (all-cause mortality, recurrent myocardial infarction and need for coronary revascularization). Genotypes were classified either as homozygous low risk (Lo) or homozygous high risk (Hi). Data Synthesis Relative risks (RR) were pooled using the random effects model. Seventeen distinct data sets that included 15,826 participants were analyzed. Ten studies (n=9807) reported number of diseased vessels at baseline. Hi genotype was associated with a 33.7% increased risk of triple vessel disease (95% CI 1.08-1.65; p=0.01). The Hi genotype was associated 0.27 higher baseline Gensini Score (95% CI 0.04-0.48; p=0.01) in 3787 individuals. The locus was not associated with Dc.PI [RR=0.21 (95% CI -0.14-0.55; p=0.25)]. The high risk genotype did not predict [[Unable to Display Character: ∆]]MLD or number of new lesions at follow-up. There was no difference between Hi and Lo genotypes in terms of all-cause mortality [RR=1.13 (95%CI 0.90-1.41;p=0.28)], recurrent myocardial infarction (95%CI 0.92-1.40; p=0.24) or frequency of coronary revascularization [RR=1.101 95% CI (0.78-1.57); p=0.56]. Conclusion An association between 9p21-3 and greater baseline severity of coronary atherosclerosis was seen in this meta-analysis. However no association was seen between 9p21-3 and adverse angiographic and clinical outcomes which may be due to diminishing genetic risk following dietary modification and statin therapy.