Association between PAI-1 4G/5G polymorphism and diabetic nephropathy: a meta-analysis in the Chinese population.

Backgrounds and Aims: Although a number of studies have been conducted on the association between plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism and diabetic nephropathy (DN) in Chinese population, this association remains elusive and controversial. To further assess the effects of PAI-1 4G/5G polymorphism on the risk of DN, a meta-analysis was performed in the Chinese population.
Methods: Relevant studies were identified using PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure, and Chinese Biology Medicine through November, 2015. Pooled odds ratios (ORs) and 95 % confidence intervals (CIs) were used to assess the strength of the associations.
Results: This meta-analysis identified nine studies, including 777 DN cases, 413 healthy controls, and 523 DM controls. In the total analyses, a significantly elevated risk of DN was associated with variants of PAI-1 4G/5G when compared with the healthy group (4G vs. 5G, OR 2.46, 95 % CI 1.45-4.16; 4G/4G vs. 5G/5G, OR 4.32, 95 % CI 1.79-10.39; 4G/4G vs. 4G/5G +5G/5G, OR 2.96, 95 % CI 1.59-5.53; 4G/4G +4G/5G vs. 5G/5G, OR 2.78, 95 % CI 1.34-5.75) and DM group (4G vs. 5G, OR 1.93, 95 % CI 1.28-2.92; 4G/4G vs. 5G/5G, OR 2.99, 95 % CI 1.44-6.21; 4G/4G vs. 4G/5G +5G/5G, OR 2.84, 95 % CI 1.77-4.54). In the subgroup analyses stratified by ethnicity and geographic areas, it revealed the significant results in Chinese Han, in North and South China.
Conclusions: This meta-analysis showed that the PAI-1 4G/4G variant, 4G allele might be risk alleles for DN susceptibility in the Chinese population, and further studies in other ethic groups are required for definite conclusions.