SLC22A1 and type 2 diabetes mellitus: A meta-analysis aimed to evaluate the associations between OCT genetic polymorphisms and metformin response and intolerance in individuals with T2D, showed that the SLC22A1 rs622342 and the GG genotype of the SLC22A1 rs628031polymorphism were associated with a reduction in HbA1c level and fasting plasma glucose level respectively (15).