ACE insertion/deletion polymorphism and diabetic nephropathy: an evidence-based meta-analysis

The angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism could influence predisposition for diabetic nephropathy (DN) by vascular modulation in the kidney, through a direct effect on cellular hypertrophy. However, studies on the association between this polymorphism and DN report conflicting results. To help determine if this association exists, we conducted a meta-analysis. Published studies until 2018 were researched from electronic databases PubMed/NCBI and Cochrane Library. Thirty studies including 4,774 DN cases and 4,357 individuals without DN were included in this meta-analysis. Extraction of data from all eligible publications was performed by two investigators independently, according to the inclusion and exclusion criteria. We used the statistical software "R" by the overall odds ratio (OR) with a 95% confidence interval to evaluate the association of ACE I/D polymorphism with a possible risk towards DN development. We included various genetic model analyses, sensitivity analyses, and assessments of bias in our metaanalysis. We found a significant association for ACE I/D polymorphism; the D allele is a predisposing factor for DN in diabetic patients. The risk for development of diabetes complications, such as DN, is highly complex and could be considered multifactorial. In summary, our meta-analysis shows that the ACE I/D polymorphism is associated with susceptibility to DN.