Assessment of Insulin Resistance and Pancreatic β-Cell Function Using Homeostatic Model Assessment Indices in Asian Indian Patients with Type 2 Diabetes Mellitus: A Case-Control Study

Abstract

Type 2 diabetes mellitus (T2DM) is characterised by the dual pathophysiological abnormalities of insulin resistance and progressive pancreatic β-cell dysfunction. Asian Indians exhibit a distinctive metabolic phenotype characterised by increased central adiposity and heightened insulin resistance at lower body mass index (BMI) values compared with Western populations, contributing to disproportionately high susceptibility to T2DM. The Homeostatic Model Assessment (HOMA) provides a simple and validated method for quantifying insulin resistance (HOMA-IR) and β-cell secretory capacity (HOMA-β) from fasting glucose and insulin concentrations. The present hospital-based case-control study included 40 patients with T2DM and 40 age- and sex-matched non-diabetic controls recruited from a tertiary care centre in North India. Anthropometric measurements and biochemical parameters including fasting plasma glucose, fasting serum insulin, glycated haemoglobin (HbA1c), HOMA-IR, and HOMA-β were assessed and compared between groups. Diabetic subjects demonstrated significantly higher waist circumference (89.18±7.28 vs 81.50±8.34 cm, p=0.001), fasting plasma glucose (173.86±69.85 vs 92.56±16.80 mg/dL, p<0.001), fasting insulin (12.35±8.98 vs 7.33±4.98 mU/L, p=0.01), HbA1c (8.05±1.43 vs 5.12±0.55%, p=0.003), and HOMA-IR (5.20±3.87 vs 1.70±1.22, p=0.001) compared with non-diabetic controls. HOMA-β was significantly lower in diabetic subjects (53.36±51.34 vs 115.34±101.40, p=0.003), indicating impaired β-cell secretory function. BMI was higher in diabetic subjects, achieving borderline significance (25.28±4.14 vs 23.37±3.52 kg/m², p=0.05). These findings confirm the dual contribution of insulin resistance and β-cell dysfunction to T2DM pathogenesis in Asian Indians and support the utility of HOMA indices as practical, cost-effective tools for metabolic risk assessment in clinical and epidemiological settings.