Antihypertensive treatment modulates the association between the D/I ACE gene polymorphism and left ventricular hypertrophy:: a meta-analysis

This meta-analysis attempted to derive pooled estimates for the putative association between echocardiographic or electrocardiographic left ventricular hypertrophy and the deletion/insertion (D/I) polymorphism of the angiotensin-l converting enzyme. Case-control studies were combined, using the Mantel and Haenszel approach. Joint P-values for continuous variables were calculated by Stouffer's method. Continuous measurements of left ventricular mass, which were reported in different units, were expressed on a percentage scale using the within-study mean of the II genotype as the denominator. The computerised database used for this analysis, included 28 reports with an overall sample size of 6638 subjects. The prevalence of the D allele was significantly lower in Japanese (37.2%) than in Caucasians (56.2%). A funnel plot including 12 case-control studies (4094 subjects) suggested that no publication bias was present. Overall, left ventricular hypertrophy was not associated with the D allele. Compared with the II genotype, the excess risks of left ventricular hypertrophy associated with DD and DI genotypes were only 14% (95% CI: 0.92-1.42; P = 0.23) and 5% (95% CI: 0.87-1.28; P= 0.61), respectively. However, the sensitivity analysis showed that in untreated hypertensive patients the Dc genotype, compared with II homozygozity, was associated with a 192% (P = 0.002) higher risk of left ventricular hypertrophy. If left ventricular mass was analysed as a continuous trait across 23 studies (5438 subjects), overall no association with the D/I polymorphism was present. However, if untreated hypertensive patients were analysed separately, echocardiographic left ventricular mass was on average 10.1% (95% CI: 4.8-15.5%; P = 0.001) higher in DD homozygotes than in the II reference group. Thus, in untreated hypertensive patients, in case-control studies as well as association studies, the D allele behaved as a marker for left ventricular hypertrophy. These findings support the hypothesis that the enhanced ACE activity associated with the D allele may promote left ventricular hypertrophy if a pathophysiologic process causing this disorder, remains unopposed by treatment.