Association of Insulin Resistance with Blood Pressure Category among Non diabetic Adults: A Cross-sectional Study from a Tertiary Care Centre, Tamil Nadu, India

Abstract

Introduction: Hypertension and insulin resistance are closely linked cardiometabolic abnormalities that jointly amplify cardiovascular risk, and South Asians tend to develop metabolic dysfunction at comparatively lower Body Mass Index (BMI). However, Indian tertiary-care data on insulin resistance across graded blood-pressure categories in non diabetic adults remain limited. Aim: To assess the association between hypertension severity and insulin resistance, estimated using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), among non diabetic adults attending a tertiary-care hospital in Southern India. Materials and Methods: This hospital-based cross-sectional study was conducted in the Department of General Medicine at Shri Sathya Sai Medical College and Research Institute, Chengalpattu, Tamil Nadu, India, over 18 months. A total of 105 non diabetic adults aged ≥40 years were recruited. Blood pressure was categorised per the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) guideline, and HOMA-IR was calculated from fasting glucose and insulin (insulin-sensitive <2.5; borderline 2.5-4.0; insulin-resistant >4.0). Analyses using Statistical Package for the Social Sciences (SPSS), version 23.0 included the Chi-square test, Analysis of Variance (ANOVA), Pearson correlation, multivariable logistic regression, and odds ratio estimation, with p-value <0.05 considered significant. Results: The mean age of participants was 54.3±10.6 years, and 61.9% were male. Central obesity was present in 76.2%, and 51.4% of the cohort was hypertensive. Definite insulin resistance was observed in 26.7% and borderline resistance in 40.0%. A progressive graded rise in insulin resistance was seen from 0% in normotension to 72.7% in stage 2 hypertension (chi-square, p-value <0.001). Hypertensive individuals had substantially higher odds of insulin resistance than non hypertensive individuals (odds ratio 6.83; 95% confidence interval 2.41-19.37; p-value <0.001). HOMA-IR showed a weak, non-significant correlation with systolic blood pressure (r=0.096, p-value=0.33) In multivariable logistic regression, BMI, systolic blood pressure, fasting glucose, and age were significant independent predictors of insulin resistance. Conclusion: Hypertension in non diabetic adults from a South Indian tertiary-care setting is strongly and progressively associated with underlying insulin resistance, with a clear doseresponse gradient across blood-pressure categories. These findings support the routine consideration of insulin resistance assessment in higher-risk hypertensive adults, particularly those with abdominal adiposity or borderline dysglycaemia, to guide earlier cardiometabolic risk stratification and intervention.