Toll like receptor 4 gene Asp299Gly polymorphism increases the risk of diabetic microvascular complications: a meta analysis

OBJECTIVE: The relationship between Toll like receptor 4(TLR4) gene Asp299Gly polymorphism and diabetic microvascular complications (DMI) is unclear. Therefore, the aim of this meta analysis was to explore the relationship between TLR4 Asp299Gly polymorphism and DMI. METHODS: System search PubMed, Web of science, Springer, Cochrane library, ELSEVIER, Wanfang database, VIP, CNKI, a case–control study of the correlation between TLR4 gene Asp299Gly polymorphism and DMI published before June 2020 was collected. RESULTS: We included 6 articles, a total of 11 studies involving patients with type 2 diabetes mellitus (T2DM) complicated by microvascular complications 1834 cases, without corresponding microvascular complications 4069 cases. TLR4 gene Asp299Gly polymorphism increased the risk of microvascular complications in T2DM (dominant model OR = 1.52, 95% CI 1.10–2.09, p = 0.01; allelic model OR = 1.42, 95% CI 1.02–1.96, p = 0.04). Subgroup analysis by race and different type of microvascular complications, we found that TLR4 gene Asp299Gly polymorphism was associated with increased risk of microvascular complications in the Caucasian population (dominant model OR = 1.69, 95% CI 1.22–2.35, P = 0.002; allelic model OR = 1.56, 95% CI 1.10–2.21, P = 0.01) and increased the risk of retinopathy in patients with T2DM(dominant model OR = 1.81, 95% CI 1.04–3.14, P = 0.03; allelic model OR = 1.77, 95% CI 1.05–2.98, P = 0.03). CONCLUSION: TLR4 gene Asp299Gly polymorphism was associated with increased risk of microvascular complications in patients with T2DM, especially diabetic retinopathy (DR).