Lipoprotein Insulin Resistance Index: A Simple, Accurate Method for Assessing Insulin Resistance in South Asians.

Context: Identification of insulin resistance (IR) in South Asians, who are at a higher risk for type 2 diabetes, is important. Lack of standardization of insulin assays limits the clinical use of insulin-based surrogate indices. The lipoprotein insulin resistance index (LP-IR), a metabolomic marker, reflects the lipoprotein abnormalities observed in IR. The reliability of the LP-IR index in South Asians is unknown. Objective: We evaluated the predictive accuracy of LP-IR compared with other IR surrogate indices in South Asians. Methods: In a cross-sectional study (n = 55), we used calibration model analysis to assess the ability of the LP-IR score and other simple surrogate indices (Homeostatic Model Assessment of Insulin Resistance, Quantitative insulin sensitivity check index, Adipose insulin resistance index, and Matsuda Index) to predict insulin sensitivity (SI) derived from the reference frequently sampled intravenous glucose tolerance test. LP-IR index was derived from lipoprotein particle concentrations and sizes measured by nuclear magnetic resonance spectroscopy. Predictive accuracy was determined by root mean squared error (RMSE) of prediction and leave-one-out cross-validation type RMSE of prediction (CVPE). The optimal cut-off of the LP-IR index was determined by the area under the receiver operating characteristic curve (AUROC) and the Youden index. Results: The simple surrogate indices showed moderate correlations with SI (r = 0.53-0.69, P < .0001). CVPE and RMSE were not different in any of the surrogate indices when compared with LP-IR. The AUROC was 0.77 (95% CI 0.64-0.89). The optimal cut-off for IR in South Asians was LP-IR >48 (sensitivity: 75%, specificity: 70%). Conclusion: The LP-IR index is a simple, accurate, and clinically useful test to assess IR in South Asians.

Predictive Role of Neutrophil to Lymphocyte Ratio in Adnexal Torsion: A Systematic Review and Meta-Analysis.

Introduction: The goal of this systematic review and meta-analysis was to consolidate the available data on the role of the neutrophil to lymphocyte ratio (NLR) in predicting adnexal torsion (AT), to help guide clinical decision-making and outcomes. Methods: We used Web of Science, PubMed, and Scopus to conduct a systematic search for relevant publications published before June 26, 2022. We reported standardized mean difference (SMD) with a 95% confidence interval (CI). Because a significant level of heterogeneity was found, we used the random-effects model to calculate pooled effects. We used the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) too for quality assessment. Results: Overall, 15 articles were included in the analysis. A random-effects model revealed that patients with AT had elevated levels of NLR compared to those with other adnexal masses (SMD = 1.06, 95%CI = 0.67 to 1.45, p < 0.001). So, NLR had diagnostic value. In the subgroup analysis according to ethnicity, we found that Caucasian patients with AT had elevated levels of NLR compared to patients who were operated due to adnexal mass and reported as having a benign ovarian cyst, without torsion (SMD = 1.12, 95%CI = 0.71 to 1.54, p < 0.001). However, in the case of East Asian patients, there was no difference between cases and controls (SMD = 0.86, 95%CI = -0.21 to 1.94, p = 0.11). The pooled sensitivity of NLR was 0.79 (95%CI = 0.72-0.85), and the pooled specificity was 0.84 (95% CI, 0.74-0.91). Conclusion: In conclusion, there has been an interest in the use of NLR as a diagnostic marker for AT.

Minimal Model-Derived Insulin Sensitivity Index Underestimates Insulin Sensitivity in Black Americans.

OBJECTIVE: To examine the ethnic differences in insulin sensitivity (SI) as measured by the minimal model approach (SI-MM) and the reference method, the euglycemic-hyperinsulinemic clamp (EHC). RESEARCH DESIGN AND METHODS: In a prospective study design, thirty Black Americans (BA) were age, sex, and BMI matched with non-Hispanic Whites (NHW). Participants underwent frequently sampled intravenous tolerance test (FSIVGTT) and EHC on 2 separate days during a single visit. RESULTS: SI-MM values were significantly lower in BA when compared with NHW (0.035 ± 0.025 vs. 0.058 ± 0.036 [dL/min]/[µU/mL]; P = 0.003). However, there were no ethnic differences in SI measured by EHC (0.028 ± 0.012 vs. 0.035 ± 0.019 [dL/min]/[µU/mL]; P = 0.18). CONCLUSIONS: SI-MM systematically underestimates SI in BA when compared with NHW. These findings suggest that studies inferring lower SI in BA based on FSIVGTT and SI-MM should be interpreted cautiously.

Increased ß-Cell Responsivity Independent of Insulin Sensitivity in Healthy African American Adults.

BACKGROUND: Primary insulin hypersecretion predicts type 2 diabetes (T2DM) independent of insulin resistance. Enhanced ß-cell glucose responsivity contributes to insulin hypersecretion. African Americans (AAs) are at a higher risk for T2DM than non-Hispanic Whites (NHWs). Whether AAs manifest primary insulin hypersecretion is an important topic that has not been examined systematically. OBJECTIVE: To examine if nondiabetic AA adults have a higher ß-cell glucose responsivity compared with NHWs. METHODS: Healthy nondiabetic AA (n = 18) and NHW (n=18) subjects were prospectively recruited. Indices of ß-cell function, acute C-peptide secretion (X0); basal (Φ B), first-phase (Φ 1), second-phase (Φ 2), and total ß-cell responsivity to glucose (Φ TOT), were derived from modeling of insulin, C-peptide, and glucose concentrations during an intravenous glucose tolerance test. Insulin sensitivity was assessed by the hyperinsulinemic-euglycemic glucose clamp technique. RESULTS: Glucose disposal rate (GDR) during clamp was similar in AAs and NHWs (GDR: [AA] 12.6 ± 3.2 vs [NHW] 12.6 ± 4.2 mg/kg fat free mass +17.7/min, P = .49). Basal insulin secretion rates were similar between the groups. AA had significantly higher X0 (4423 ± 593 vs 1807 ± 176 pmol/L, P = .007), Φ 1 [377.5 ± 59.0 vs 194.5 ± 26.6 (109) P = 0.03], and Φ TOT [76.7 ± 18.3 vs 29.6 ± 4.7 (109/min), P = 0.03], with no significant ethnic differences in Φ B and Φ 2. CONCLUSIONS: Independent of insulin sensitivity, AAs showed significantly higher first-phase and total ß-cell responsivity than NHWs. We propose that this difference reflects increased ß-cell responsivity specifically to first-phase readily releasable insulin secretion. Future studies are warranted to identify mechanisms leading to primary ß-cell hypersensitivity in AAs.