ABSTRACT
<p><b>INTRODUCTION</b>Metabolic heterogeneity among obese individuals is thought to translate into variations in cardiovascular risk. Identifying obese people with an unfavourable metabolic profile may allow preventive strategies to be targeted at high-risk groups. This study aimed to identify clinical, biochemical and immunological differences between insulin-sensitive and insulin-resistant obese subgroups, to understand the population-specific pathophysiological basis of the adverse cardiovascular risk profile in the latter group.</p><p><b>METHODS</b>Cardiovascular risk indicators, including anthropometric parameters, blood pressure, acanthosis nigricans area, and related biochemical, endocrine and inflammatory markers, were determined in 255 healthy South Asian volunteers aged 18-45 years, with a 2:1 ratio of obese/overweight to normal-weight individuals. Lifetime atherosclerotic cardiovascular disease (ASCVD) risk was also calculated.</p><p><b>RESULTS</b>Body mass index (BMI) and insulin sensitivity-based tertiles independently showed incremental trends in waist-hip ratio, skinfold thickness, acanthosis nigricans area, blood pressure, serum lipids, hepatic enzymes, adipokines, inflammatory markers and ten-year ASCVD risk. The anthropometric, biochemical and inflammatory parameters of obese insulin-sensitive and obese insulin-resistant groups differed significantly. Extreme group analysis after excluding the middle tertiles of both insulin resistance and BMI also showed significant difference in anthropometric indicators of cardiovascular risk and estimated lifetime ASCVD risk between the two obese subgroups.</p><p><b>CONCLUSION</b>Obese insulin-sensitive individuals had a favourable metabolic profile compared to the obese insulin-resistant group. The most consistent discriminative factor between these phenotypic classes was anthropometric parameters, which underscores the importance of clinical parameters as cardiovascular risk indicators in obesity.</p>
ABSTRACT
<p><b>INTRODUCTION</b>With advancement in the understanding of the pathogenesis underlying diabetes mellitus (DM), the boundary between type 1 and type 2 DM (T1DM and T2DM) does not seem to be as clear cut as previously thought. This study was designed to test the possibility of overlap between the spectra of immune-mediated DM and insulin resistance.</p><p><b>METHODS</b>To test for the possibility of overlap, we looked for autoantibodies typical of T1DM in patients with classical T2DM, and insulin resistance in patients with T1DM. Autoantibodies against islet cell antigen, glutamic acid decarboxylase-65 and insulinoma-associated antigen-2 were tested in 82 patients with T2DM and 27 patients with T1DM. The patients had been diagnosed on clinical criteria using standard laboratory techniques. Clinical parameters of diagnostic importance were noted, and homeostatic model assessment of insulin resistance (HOMA-IR) was calculated using fasting insulin and fasting blood glucose ratio.</p><p><b>RESULTS</b>Autoantibodies against one or more beta cell antigens were detected in 12.19% of patients clinically diagnosed to have T2DM, and insulin resistance (HOMA-IR > 2.5) was diagnosed in 37.03% of patients with T1DM. It was not possible to identify any combination of clinical or biochemical markers that could predict autoantibody positivity in T2DM patients. T1DM patients with insulin resistance had a significantly higher body mass index than their insulin-sensitive counterparts (p = 0.02).</p><p><b>CONCLUSION</b>Autoantibodies against beta cell antigens are detectable in insulin-resistant T2DM patients, and insulin resistance may be present in relatively overweight T1DM patients. No differentiating clinical features that might predict autoantibody positivity in T2DM patients were found.</p>