Validity and reliability of simple surrogate indexes to evaluate beta-cell function and insulin sensitivity

BACKGROUND: Simple surrogate indexes (SSI) to assess beta-cell function, insulin sensitivity (IS) and insulin resistance (IR) are an easy and economic tool used in clinical practice to identify glucose metabolism disturbances. AIM: To evaluate the validity and reliability of SSI that estimate beta-cell function, IS and IR using as a reference the parameters obtained from the frequently sampled intravenous glucose tolerance test (FSIVGTT). MATERIAL AND METHODS: We included 62 subjects aged 20-45 years, with a normal body mass index and without diabetes or prediabetes. SSI were compared with the acute insulin response to glucose (AIRg), insulin sensitivity index (Si) and disposition index (DI) obtained from the FSIVGTT using the minimal model approach. Half of the participants (n = 31) were randomly selected for a second visit two weeks later to evaluate the reliability of all the variables. RESULTS: HOMA1-%B and HOMA2-%B had a significant correlation with AIRg (Spearman Rho (rs) = 0.33 and 0.37 respectively, p 0.50) with Si were fasting insulin, HOMA1-IR, HOMA2-IR, HOMA1-%S, HOMA2-%S, QUICKI, and the McAuley index. The parameters that showed good reliability with an intraclass correlation coefficient (ICC) > 0.75 were AIRg, HOMA1-%S, HOMA2-%S, and QUICKI. Conclusions: Our results suggest that most of the SSI are useful and reliable.

ANTECEDENTES: Los índices simples subrogados (ISS) que evalúan la función de célula beta, sensibilidad a la insulina (SI) y resistencia a la insulina (RI) son herramientas sencillas y económicas que se usan en la práctica clínica para identificar alteraciones del metabolismo de la glucosa. OBJETIVO: Evaluar la validez y confiabilidad de ISS para estimar la función de célula beta, SI y RI usando como referencia los parámetros de la prueba de tolerancia a la glucosa intravenosa con muestreo frecuente (FSIVGTT). MATERIAL Y MÉTODOS: Se incluyeron 62 sujetos de 20-45 años, con índice de masa corporal normal y sin diabetes mellitus o prediabetes. Los ISS se compararon con la respuesta aguda de la insulina a la glucosa (AIRg), índice de sensibilidad a la insulina (Si) e índice de disposición (DI) obtenidos de la FSIVGTT en base al modelo mínimo. La mitad de los participantes (n = 31) se seleccionaron aleatoriamente para acudir dos semanas después y evaluar la confiabilidad de todas las variables. RESULTADOS: HOMA1-%B y HOMA2-%B presentaron una correlación significativa con AIRg (Rho de Spearman (rs) = 0,33 and 0,37, respectivamente, p 0,50) con Si fueron insulina en ayuno, HOMA1-IR, HOMA2-IR, HOMA1-%S, HOMA2-%S, QUICKI y el índice de McAuley. Los parámetros que tuvieron buena confiabilidad (coeficiente de correlación intraclase > 0,75) fueron AIRg, HOMA1-%S, HOMA2-%S y QUICKI. Conclusiones: La mayoría de los ISS son instrumentos útiles y confiables.

Validity and reliability of simple surrogate indexes to evaluate beta-cell function and insulin sensitivity.

BACKGROUND: Simple surrogate indexes (SSI) to assess beta-cell function, insulin sensitivity (IS) and insulin resistance (IR) are an easy and economic tool used in clinical practice to identify glucose metabolism disturbances. AIM: To evaluate the validity and reliability of SSI that estimate beta-cell function, IS and IR using as a reference the parameters obtained from the frequently sampled intravenous glucose tolerance test (FSIVGTT). MATERIAL AND METHODS: We included 62 subjects aged 20-45 years, with a normal body mass index and without diabetes or prediabetes. SSI were compared with the acute insulin response to glucose (AIRg), insulin sensitivity index (Si) and disposition index (DI) obtained from the FSIVGTT using the minimal model approach. Half of the participants (n = 31) were randomly selected for a second visit two weeks later to evaluate the reliability of all the variables. RESULTS: HOMA1-%B and HOMA2-%B had a significant correlation with AIRg (Spearman Rho (rs) = 0.33 and 0.37 respectively, p < 0.01). The SSI evaluating IS/IR that showed stronger correlation (rs > 0.50) with Si were fasting insulin, HOMA1-IR, HOMA2-IR, HOMA1-%S, HOMA2-%S, QUICKI, and the McAuley index. The parameters that showed good reliability with an intraclass correlation coefficient (ICC) > 0.75 were AIRg, HOMA1-%S, HOMA2-%S, and QUICKI. CONCLUSIONS: Our results suggest that most of the SSI are useful and reliable.

Sucralose Consumption over 2 Weeks in Healthy Subjects Does Not Modify Fasting Plasma Concentrations of Appetite-Regulating Hormones: A Randomized Clinical Trial.

BACKGROUND: The effect of nonnutritive sweeteners on appetite is controversial. Some studies have found changes in certain appetite control hormones with sucralose intake that may be through interaction with sweet taste receptors located in the intestine. OBJECTIVE: The aim of this study was to evaluate whether sucralose consumption could produce changes in fasting plasma concentrations of appetite-regulating hormones, including glucagon-like peptide 1, ghrelin, peptide tyrosine tyrosine, and leptin, and secondarily in insulin resistance. DESIGN: A 2-week parallel randomized clinical trial with an additional visit conducted 1 week after dosing termination. PARTICIPANTS/SETTING: Sixty healthy, normal-weight individuals, without habitual consumption of nonnutritive sweeteners were recruited from July 2015 to March 2017 in Mexico City. INTERVENTION: Daily sucralose consumption at 15% of the acceptable daily intake by using commercial sachets added to food. The control group followed the same protocol without an intervention. MAIN OUTCOMES MEASURED: Fasting concentrations of appetite regulating hormones before and after the intervention. Fasting glucose and insulin concentrations were measured to assess insulin resistance as a secondary outcome. STATISTICAL ANALYSIS PERFORMED: Basal and final concentrations were compared using Wilcoxon matched-pairs test and Mann-Whitney U test for analysis between groups. Repeated measures analysis of variance was used to evaluate changes in the homeostasis model assessment of insulin resistance. RESULTS: Sucralose was not associated with changes in any of the hormones measured. One week postintervention, an incremental change (P=0.04) in the homeostasis model assessment of insulin resistance was found in the intervention group. CONCLUSIONS: Sucralose intake is not associated with changes in fasting concentrations of glucagon-like peptide 1, ghrelin, peptide tyrosine tyrosine, or leptin. An increase in the homeostasis model assessment of insulin resistance observed only at 1 week postdosing is of unknown clinical significance, if any.