This search strategy was as follows; (thiazolidinediones OR rosiglitazone OR troglitazone OR pioglitazone) AND (biguanide OR metformin) AND (insulin sensitivity OR insulin resistance OR insulin action) AND (glucose tolerance OR glucose production OR glucose intolerance) AND (T2DM OR Type II Diabetes mellitus). Here, INS is linked to type 2 diabetes mellitus.