The role of the TNF-α gene -308 G/A polymorphism in the development of diabetic nephropathy: An updated meta-analysis.

Background And Aims: Several studies have tried to link the relationship of tissue necrosis factor-alpha (TNF-α) -308 G/A polymorphism with the development of diabetic nephropathy (DN). However, these studies failed to reach a consensus due to conflicting results. This meta-analysis was done to thoroughly investigate the correlation between the polymorphism and DN development.

Methods: To carry out the objective, patients with type 2 diabetes mellitus (T2DM) were used as controls, while patients who developed DN were utilized as cases. Eight studies (i.e., published between 2007 and 2018) were included in the present meta-analysis. Review Manager 5.3 was used to compute for the odds ratios (OR) and 95% confidence interval (CI) of the overall and post-outlier outcomes.

Results: Overall, an association between DN development and the -308 G/A polymorphism was observed. However, Galbraith's plot analysis (as analyzed using Meta-Essentials) led to the removal of two studies, which significantly reduced heterogeneity. Post-outlier outcomes show significant results in the allelic (OR: 1.23; 95% CI: 1.01-1.50; p = 0.04) and co-dominant (OR: 1.60; 95% CI: 1.02-2.51; p = 0.04) models.

Conclusion: T2DM individuals with the -308 G/A polymorphism in the TNF-α gene are more likely to develop DN.