Surrogate markers of insulin resistance: A review

Table 1 Various methods to measure insulin resistance

S No	Method	Comments	Advantages	Disadvantages
1	Hyperinsulinemic euglycemic glucose clamp	Gold standard method for quantifying insulin sensitivity	Direct measure of insulin under steady-state conditions	Laborious, involves intra venous infusion of insulin, frequent blood sampling
2	Oral glucose tolerance test	Clinically used to detect glucose intolerance	Helps in estimating other surrogate indices	Useful for glucose tolerance but not for IR
3	Fasting insulin	Most practical method to measure IR	Detects insulin resistance before clinical disease appears	Lack of standardization of the insulin assay procedure
4	Glucose/insulin ratio (G/I ratio)	comparable to insulin sensitivity measured by the FSIVGTTT	Highly sensitive & specific for insulin sensitivity	Does not aptly reveal the physiology of insulin sensitivity
5	Insulinogenic index (IGI)	index of β-cell function δI (0-30 min)/δG (0-30 min)	Measure of first-phase insulin response to glucose challenge	Not broadly validated
6	Homeostasis model assessment	Assesses inherent β-cell function and insulin sensitivity HOMA-IR = (G × I)/22.5	Simple, minimally invasive, predicts fasting steady-state G and I levels	Insulin sensitivity in subjects treated with insulin needs further validation
7	Quantitative insulin sensitivity check index (QUICKI)	Mathematical transformation of FBG and insulin QUICKI = 1/[log (IμU/mL) + log(G mg/dL)]	Consistent, precise index of insulin sensitivity, minimally invasive	Normal range to be established for each laboratory due to significant inter laboratory variations in insulin assay
8	Minimal model analysis of frequently sampled intravenous glucose tolerance test	Indirect measure of insulin sensitivity/resistance	Analysis using the computer program MINMOD	Multiple blood sampling
9	Glucose insulin (GI) product	Index of whole-body insulin sensitivity
10	Fasting insulin resistance index (FIRI)	(fasting G × fasting I)/25

G: Glucose; I: Insulin; IR: Insulin resistance; FBG: Fasting blood glucose.

Table 2 Various derived surrogate markers of insulin resistance

S No	Method	Measurement	Comments
1	Matsuda index	10 000/√ (fasting G × fasting I) (mean G × mean I)	Represents both hepatic and peripheral tissue sensitivity to insulin
2	Gutt index	75 000 + (G0 - G120) (mg/dL) × 0.19 × BW/120 × Gmean(0, 120) (mmol/L) × Log [Imean(0, 120)] (mU/L)	Good to predict onset of type 2 diabetes
3	Stumvoll index	0.156 - 0.0000459 × I120 (pmol/L) – 0.000321 × I0 (pmol/L) – 0.00541 × G120 (mmol/L)	Utilizes demographic data like age, sex and BMI along with plasma glucose and insulin to predict insulin sensitivity
4	Avignon index	Sib = 108/[I0 (mU/L) × G0 (mmol/L) × VD) Si2h = 108/(I120 (mU/L) × G120 (mmol/L) × VD]	Determines glucose tolerance and insulin sensitivity in single test
5	Oral glucose insulin sensitivity index	G and I concentrations from a 75 g OGTT at 0, 2, and 3 h (3 h OGTT) or at 0, 1.5, and 2 h (2 h OGTT). The formula includes six constants
6	Log (HOMA-IR)	Evaluates insulin resistance in insulin-resistant states like glucose intolerance and mild to moderate diabetes

Sib: Derived from fasting plasma insulin and glucose; Si2h: Derived from fasting plasma insulin and glucose ant 2 h of OGTT; OGTT: Oral glucose tolerance test.

Table 3 Imminent markers of insulin resistance

S No	Marker
1	Insulin growth factor binding protein-1 (IGFBP-1)
2	sCD36 (solubleCD36)
3	C-reactive protein (CRP)
4	Ferritin
5	Adiponectin
6	Tumour necrosis factor (TNF alpha)
7	Resistin
8	C3 complement
9	Glycosylated hemoglobin (Hb)A1c
10	Protein kinase C (PKC) in microangiopathy
11	Sex hormone-binding globulin (SHBG) in hyperandrogenic syndrome