Fat Mass Accounts for Insulin Resistance Impact on Functional Decline and Mortality in Nondiabetic Older Adults.

OBJECTIVE: To assess the potential role of body composition in the association of insulin resistance (IR) with functional decline and mortality in nondiabetic older persons. DESIGN: Longitudinal population-based cohort of community-dwelling people from Toledo, Spain, aged 65 years or older. SETTING AND PARTICIPANTS: A total of 1114 nondiabetic persons from the Toledo Study of Healthy Aging cohort (mean age: 74.5, 56.10% female) with complete data at baseline were included. Only 914 participants had fully assessment of functional evaluation during the follow-up period. METHODS: IR was determined by the homeostasis model assessment index (HOMA-IR) at baseline while frailty was assessed by the Frailty Trait Scale-5 (FTS-5) at baseline and after 2.99 years' median follow-up period. A total of 319 participants experienced functional decline (2.5-point reduction in the FTS-5 score). A total of 143 deaths were recorded (6.31 years median follow-up) from the Spanish National Death Index. Body compositions were determined using dual-energy x-ray absorptiometry. Multivariate regression models analyzed the effect of HOMA-IR on outcomes, with age, sex, Charlson index, and number of medications included in the basic adjustment model. RESULTS: A 1-logaritmic unit increment in HOMA-IR increased the risk of functional decline after basic adjustment [odds ratio (95% confidence interval): 1.41 (1.09-1.83), P = .009]. This significant association was lost when further adjusted for total fat mass [1.14 (0.86-1.50)] and trunk fat mass [1.03 (0.77-1.37)], which accounted for 62.92% and 91.49% of the association. HOMA-IR was inversely associated with mortality risk [hazard ratio 0.66 (0.49-0.87), P = .0037], an association lost after adjustment for total fat mass [0.74 (0.55-1.01)] and trunk fat mass [0.80 (0.58-1.09)], accounting for 29.05% and 45.78% of the association. Adjustment by lean mass did not modify any of the associations. CONCLUSIONS AND IMPLICATIONS: Body fat mass, especially in the trunk region, mediates the association of IR with functional decline and to a lesser extent with reduced risk of mortality in nondiabetic older subjects.

Valoración del uso del índice ictérico como parámetro para la gestión de la determinación de la bilirrubina total / Use of icteric index as a parameter for the management of the determination of total bilirubin

Introducción: El exceso de pruebas enviadas al laboratorio, en numerosas ocasiones, no aporta un valor añadido, lo que nos lleva a plantearnos su uso eficiente. La bilirrubina es una magnitud bioquímica clásica para el estudio de la alteración hepática, y el índice ictérico es una medida indirecta para la determinación semicuantitativa de la bilirrubina. Objetivos: Evaluar la utilidad del índice ictérico para detectar a pacientes con concentraciones de bilirrubina en suero superiores o inferiores a 1,20mg/dL, de manera que interese valorar la determinación de bilirrubina, y calcular el ahorro que supondría la aplicación de este algoritmo. Material y métodos: Se realizó un estudio retrospectivo para determinar la correlación entre el índice ictérico y la bilirrubina, y un análisis de regresión. La eficacia diagnóstica del índice ictérico se estudió mediante una curva Receiver Operating Characteristic, determinando el valor de corte del índice ictérico que permite discriminar valores de bilirrubina superiores e inferiores a 1,20mg/dL. Se calculó la sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo. Resultados y discusión: El análisis estadístico indicó una buena correlación entre ambas variables. El estudio de eficacia diagnóstica mostró que el punto de corte índice ictérico=2 tiene un alto valor predictivo negativo y una alta sensibilidad y especificidad. Conclusiones: Los valores de índice ictérico correlacionan bien con la bilirrubina, permitiendo el cribado de la hiperbilirrubinemia. Así se evitaría realizar el 89,72% de las bilirrubinas, informándose como<1,20mg/dL aquellas muestras con índice ictérico≤1, suponiendo un ahorro importante al laboratorio

Introduction: As too many laboratory tests may not represent significant improvements, their efficient use should be considered. Bilirubin is a classical biochemical marker of hepatic alterations, and the icteric index is an indirect measure for the semi-quantitative determination of jaundice. Objectives: To evaluate the use of the icteric index in the identification of patients with serum bilirubin concentrations with values higher or lower than 1.20mg/dL, as well as to assess the determination of bilirubin, and to evaluate the savings that the application of this algorithm would represent. Material and methods: A retrospective study was performed to determine the relationship between icteric index and total bilirubin. A regression analysis was also performed. The diagnostic efficiency of the index was studied using a Receiver Operating Characteristic curve to determine the cut-off value that would allow to distinguish bilirubin values higher and lower than 1.20mg/dL. The sensitivity and specificity, positive predictive value and negative predictive value were also calculated. Results and discussion: The statistical analysis showed a high correlation between both variables. The study of diagnostic efficacy showed that to use an icteric index equal to 2 as a cut-off point yields a high negative predictive value, sensitivity and specificity. Conclusions: Icteric index values are well correlated with bilirubin, which allows filtering for hyperbilirubinaemia. Therefore, 89.72% of bilirubin requests would not be needed. With those samples with icteric index ≤ 1 subsequently being reported as<1.20mg/dL, thus representing a savings to the laboratory