Comparison of insulin resistance by indirect methods - HOMA, QUICKI and McAuley - with fasting insulin in patients with type 2 diabetes in Galle,Sri Lanka: A pilot study

Background: To investigate importance of fasting insulin (FI) as a diagnostic test for insulin resistance (IR) and to compare with other standard methods McAuley (McA), HOMA and QUICKI indices in Diabetes Mellitus (DM). Method: 42 diabetic patients who have been already diagnosed were used in our study. They were investigated for fasting blood glucose (FBS), FI, LDL, Triglycerides (TG), total cholesterol (TC) and HDL levels. IR was calculated by McA, HOMA, QUICKI indices and by FI. Results: 81% of patients were insulin resistant by McA and FI in our study group. 93% were detected as insulin resistant by HOMA and QUICKI. IR by FI was further compared with HOMA and QUICKI and 81% of patients were found to be insulin resistant by FI, HOMA and QUICKI. Results showed that there was a significant correlation between FI and McA in expressing IR in our study group (p <0.01, r = -0.849). Further, FI had a statistically significant correlation with HOMA and QUICKI indices (p <0.01, r = 0.906 and p <0.01 r = -0.822 respectively). Conclusion: FI measurement alone in diabetic patients has detected IR in 81% of patients, similar to the other standard methods (McA; 81%, HOMA and QUICKI; 93%). We further identified that FI as a diagnostic test of IR had substantial correlation with McA. Our results recommend further studies to see the possibility of taking fasting insulin to determine IR in type 2 diabetic population