Objective Plasminogen activator inhibitor 1 (PAI-1) is thought to play a role in the pathogenesis of obesity and insulin resistance. A connection between gestational diabetes mellitus and the functional -675 PAI-1 genotype has been reported. Therefore, we examined the role of the PAI-1 gene polymorphism in kidney transplant recipients. Methods A total of 376 kidney transplant recipients were prospectively screened for posttransplant diabetes mellitus (PTDM). Eighty-one (21.5%) patients were diagnosed with PTDM and the other 295 patients were non-diabetic following kidney transplantation. DNA samples were isolated from the sera and analyzed for the functional − 675 4G/5G promoter polymorphisms of the PAI-1 gene. Results Kidney transplant recipients with PTDM were significantly associated with tacrolimus use (p = 0.03), older age (p = 0.036), and higher body mass index (p = 0.001). The genotype distribution was significantly different between the patients with PTDM (genotype 4G/4G:4G/5G:5G/5G = 33.3%:60.5%:6.2%) and those without PTDM (genotype 4G/4G:4G/5G:5G/5G = 36.9%:44.1%:19.0%) (p = 0.018). Patients with homozygosity for 5G had a significantly lower rate of PTDM (aOR, 0.286, p = 0.022) and higher cumulative event-free probability of time to PTDM (log rank test, p = 0.0058). Conclusion Homozygosity for the 5G allele of the PAI-1 gene constitutes a protecting factor for the development of PTDM. Our findings are similar to a previous study on gestational diabetes mellitus, and strongly support a possible genetic role of PAI-1 in the development of PTDM.
