Investigation of the relationship of obesity indexs and insulin resistance

Objective: Insulin resistance (IR) is a clinically significant abnormality that can progress to diabetes after the development of compensatory hyperinsulinemia and βcell dysfunction. Early identification of people at high risk for insulin resistance, early diagnosis and treatment of insulin resistance could be a way to prevent diabetes and its complications. Laboratory tests in primary health care are very limited. In our study, we aimed to investigate the implementation of obesity indices to predict IR in primary health care with limited laboratory resources and to prevent the development of diabetes mellitus (DM), to protect the patient from complications of diabetes, and to reduce the associated mortality and morbidity. Materials and Methods: Our study was formed by the retrospective evaluation of patients aged 18-65 years, who did not have any endocrinological disorders, who applied to the Bezmialem Vakıf University Faculty of Medicine, Family Medicine Outpatient Clinic between January 2016 and June 2020. Patients' age, gender, smoking, alcohol use, exercise, family history of diabetes mellitus, marital status, educational status, and comorbidities were questioned. Obesity indices (height, weight, body mass index (BMI), body fat ratio, waist circumference, waist/height ratio, skinfold thickness) measured during the examination. Blood tests obtained after 8 hours of fasting; Cr, BUN, AST, ALT, fasting glucose, insulin, HOMA-IR, HbA1C, HDL, LDL, TG, Total cholesterol, Non-HDL cholesterol were recorded and evaluated. The relationship between obesity indices and HOMA-IR was examined and its statistical significance was investigated. When evaluating the study data, Youden index, Kolmogrov Smirnov and Shapiro Wilk tests, QQ plot and histogram graphs, independent sample t-test, Mann Whitney U Pearson Chi-square test, Fisher's exact test, ROC curve analysis, Area under the curve (AUC), pROC package, Spearman correlation, binary logistic regression analysis were used and p<0.05 was considered significant. Results: Our study included 110 patients with insulin resistance and 117 without insulin resistance; 175 women and 52 men, in total 227 patients were included. A statistically significant positive correlation was found between BMI, waist circumference, fat ratio, waist/height ratio, biceps skinfold thickness, triceps skinfold thickness, subscapular skinfold thickness and HOMA-IR (p<0.001). When insulin resistance and obesity indices were analyzed with binary logistic regression, all variables were found to be statistically significant (p<0.001). Conclusion: The results of our study demonstrate the relationship between obesity indices and IR, supporting previous literature. The strongest relationship between IR and obesity indices was found with subscapular skinfold thickness. The implementation of anthropometric measurements at routine primary health care practice, if conditions of clinic permit, may provide additional benefit in terms of a pre-diabetes diagnosis. However, we think that our study is important for the Turkish population, since there are not enough studies on this subject in our country. Considering the previous literature data; supporting this subject with larger studies to be conducted in Turkey will contribute to improve mortality and morbidity by enabling us to identify insulin resistance, despite of lacking detailed laboratory tests, and to take precautions within the scope of preventive medicine before diabetes and related complications develop. Keywords: Insulin Resistance, Obesity Indices, Anthropometric Measurements