HOMA equations have been one of the tools widely used in research to estimate insulin resistance. The two equations (which use fasting blood levels) are as follows, with HOMA-IR used to assess insulin resistance and HOMA-B used to assess pancreatic beta–cell function [13, 14] :
HOMA-IR= (glucose in mmol/L x insulin in mIU/mL)/22.5
HOMA-B= (20 x insulin in mIU/mL)/(glucose in mmol/L - 3.5)
Fasting insulin levels can serve as a tool to help guide the choice of therapy in patients newly diagnosed with type 2 diabetes. A study by Saxena et al found that such patients with normal to low initial fasting serum insulin levels responded better to glipizide than to metformin. On the other hand, those with high fasting serum insulin levels responded significantly better to metformin than to glipizide.