Chronic kidney disease staging with cystatin C or creatinine-based formulas: flipping the coin.

Background: Chronic kidney disease (CKD) affects 10-13% of the population worldwide. CKD classification stratifies patients in five stages of risk for progressive renal disease based on estimated glomerular filtration rate (eGFR) by formulas and albuminuria. However, the reliability of formulas to reflect real renal function is a matter of debate. The effect of the error of formulas in the CKD classification is unclear, particularly for cystatin C-based equations. Methods: We evaluated the reliability of a large number of cystatin C and/or creatinine-based formulas in the definition of the stages of CKD in 882 subjects with different clinical situations over a wide range of glomerular filtration rates (GFRs) (4.2-173.7 mL/min). Results: Misclassification was a constant for all 61 formulas evaluated and averaged 50% for creatinine-based and 35% for cystatin C-based equations. Most of the cases were misclassified as one stage higher or lower. However, in 10% of the subjects, one stage was skipped and patients were classified two stages above or below their real stage. No clinically relevant improvement was observed with cystatin C-based formulas compared with those based on creatinine. Conclusions: The error in the classification of CKD stages by formulas was extremely common. Our study questions the reliability of both cystatin C and creatinine-based formulas to correctly classify CKD stages. Thus the correct classification of CKD stages based on estimated GFR is a matter of chance. This is a strong limitation in evaluating the severity of renal disease, the risk for progression and the evolution of renal dysfunction over time.

Sex hormones and the total testosterone:estradiol ratio as predictors of severe acute respiratory syndrome coronavirus 2 infection in hospitalized men.

BACKGROUND: The predictive ability of the early determination of sex steroids and the total testosterone:estradiol ratio for the risk of severe coronavirus disease 2019 or the potential existence of a biological gradient in this relationship has not been evaluated. OBJECTIVES: To assess the relationship of sex steroid levels and the total testosterone:estradiol ratio with the risk of severe acute respiratory syndrome coronavirus 2 infection in men, defined as the need for intensive care unit admission or death, and the predictive ability of each biomarker. MATERIALS AND METHODS: This was a prospective observational study. We included all consecutive adult men with severe acute respiratory syndrome coronavirus 2 infections in a single center admitted to a general hospital ward or to the intensive care unit. Sex steroids were evaluated at the centralized laboratory of our hospital. RESULTS: We recruited 98 patients, 54 (55.1%) of whom developed severe coronavirus disease in 2019. Compared to patients with nonsevere coronavirus disease 2019, patients with severe coronavirus disease 2019 had significantly lower serum levels of total testosterone (111 ± 89 vs. 191 ± 143 ng/dL; p < 0.001), dehydroepiandrosterone (1.69 ± 1.26 vs. 2.96 ± 2.64 ng/mL; p < 0.001), and dehydroepiandrosterone sulfate (91.72 ± 76.20 vs. 134.28 ± 98.261 µg/dL; p = 0.009), significantly higher levels of estradiol (64.61 ± 59.35 vs. 33.78 ± 13.78 pg/mL; p = 0.001), and significantly lower total testosterone:estradiol ratio (0.28 ± 0.31 vs. 0.70 ± 0.75; p < 0.001). The lower the serum level of androgen and the lower the total testosterone:estradiol ratio values, the higher the likelihood of developing severe coronavirus disease 2019, with the linear trend in the adjusted analyses being statistically significant for all parameters except for androstenedione (p = 0.064). In the receiver operating characteristic analysis, better predictive performance was shown by the total testosterone:estradiol ratio, with an area under the curve of 0.77 (95% confidence interval 0.68-0.87; p < 0.001). DISCUSSION AND CONCLUSION: Our results suggest that men with severe acute respiratory syndrome coronavirus 2 infection, decreased androgen levels and increased estradiol levels have a higher likelihood of developing an unfavorable outcome. The total testosterone:estradiol ratio showed the best predictive ability.

TNF Inhibitors Exert a "Hidden" Beneficial Effect in the Cardiovascular Lipoprotein Profile of RA Patients.

Purpose: A high cardiovascular risk has been described in patients with rheumatoid arthritis (RA); the effects of different biological agents have also been described in these patients. The aim of the present study is to examine the effects of tumor necrosis factor inhibitors (TNFi) in the lipoprotein profile of RA patients using a broad laboratory assessment including a large number of non-routine tests. Patients and Methods: RA patients treated with and without TNFi (70 patients in each group) were cross-sectionally compared regarding a broad spectrum of lipoprotein parameters including serum levels of total and HDL, LDL and VLDL cholesterol triglycerides, lipoprotein A (LpA), apolipoprotein A1 (Apo A), B100 (Apo B) and paroxonase. For each lipoprotein subfraction (HDL, LDL and VLDL), we assess specific concentrations of cholesterol, triglycerides, phospholipids and proteins and total mass of each one. Additionally, HDL Apo A, LDL and VLDL Apo B concentrations and number of particles of LDL and VLDL were also determined. Exploratory univariate and multivariate analyses of the different variables were performed. Results: Seventy patients in each subset were enrolled. Patients on treatment with TNFi showed a trend to be younger and to have a longer disease duration. Regarding the lipoprotein analyses, borderline significant higher levels of serum Apo A were detected and an independent association with lower HDL mass, LDL triglyceride, VLDL cholesterol, VLDL Apo B, VLDL mass, number of VLDL cholesterol molecules and number of particles of VLDL was clearly observed. Conclusion: TNFi treatment was associated with beneficial atherogenic effects at the lipoprotein level especially centered in the VLDL-related parameters consistent with a reduction of the atherogenic risk.

Impacto del empleo de umbrales específicos de referencia en el diagnóstico de las alteraciones funcionales tiroideas en la mujer gestante / Impact of using specific reference intervals on the diagnosis of thyroid dysfunction during pregnancy

Objetivo: Establecer los umbrales específicos de referencia de cada uno de los parámetros de función tiroidea en cada trimestre de la gestación y determinar el impacto del uso de umbrales no específicos en el diagnóstico de las alteraciones funcionales en el primer trimestre. Métodos: Entre enero y septiembre de 2014 se contactaron 759 mujeres embarazadas con edad mayor de 18 años y sin alteraciones funcionales tiroideas conocidas. Tras excluir a todas las pacientes que no completaron el seguimiento durante toda la gestación y las que presentaron inmunidad tiroidea positiva, 411 gestantes configuraron nuestra población de referencia. Se determinaron los niveles de TSH, T4L y T3L en cada trimestre, los anticuerpos antiperoxidasa tiroidea y antitiroglobulina en el primero y se recogió una muestra de orina en los trimestres primero y tercero para la determinación del yodo urinario. Resultados: Un total de 411 gestantes completaron el seguimiento en los 3 trimestres. Un 38,69% consumían sal yodada y un 72,20% suplementos yodados. Los valores de referencia de TSH expresados como mediana y percentiles 2,5 y 97,5 fueron: 1,53 μUI/ml (0,26-3,95), 1,90 μUI/ml (0,78-3,85) y 1,89 μUI/ml (0,71-3,61) en el primer, segundo y tercer trimestre, respectivamente. El nivel de yoduria fue de 171,31 μg/l (90,7-274,9) en el primer trimestre y de 190,37 μg/l (96,44-360,38) en el tercero. La aplicación en el primer trimestre de los umbrales propuestos por las sociedades internacionales ocasionaría una clasificación errónea del 19,8% de las gestantes en relación con su función tiroidea, mientras que los umbrales no específicos de nuestro laboratorio lo harían en el 8,52%. Conclusiones: La utilización de umbrales no específicos para el diagnóstico de las alteraciones funcionales tiroideas durante la gestación ocasiona un importante porcentaje de errores de clasificación, contribuyendo a una atención inadecuada.

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