Comparison of low-density lipoprotein obtained from the Friedewald formula and new formulae in a heterogeneous population.
Artículo de revista
2011-11-11
Introduction: Although the levels of low-density lipoprotein (LDL-C) should ideally be determined by beta quantification
or enzymatic methods, there are limitations in developing countries. The goal of this study is to compare LDL-C obtained
through three formulae (LDL-Cnf) with LDL-C obtained through the Friedewald formula (LDL-Cf) using LDL-C through
enzymatic methods as the most-accepted reference method in clinical practice (LDL-Cr).
Methods: A concordance study was carried out in a reference laboratory in Cali, Colombia. The three formulae were (mg/
dl): Men with triglycerides under 400 mg/dl: LDL-C = Total Cholesterol (TC) - triglycerides (TG) /6.5) - 45; men with
triglycerides equal to or greater than 400 mg/dl: LDL-C = (TC - (TG / 7)) -50 and women: LDL-C = (TC-(TG /6.5)) - 70.
Results: Three-hundred fifteen values were obtained of which 53% were for women. The mean age and LDL-Cr were 54
years (±15.8) and 112.1 mg/dl (±32.5), respectively. The median (interquartile range, mg/dl) of TC, high-density lipoprotein
(HDL-C) and TG were 204 mg/dl (171-229), 51 mg/dl (41-61), and 156 mg/dl (99-237), respectively. There were no
differences between mean values of LDL-Cr and LDL-Cnf (113.48 vs. 112.67 mg/dl; p=0.45). The intraclass correlation
coefficient among LDL-Cr and LDL-Cf and LDL-Cnf were high (R=0.93 and 0.92, respectively). The correlation between
LDL-Cf and LDL-Cnf was 0.95. There is no difference between the areas under the receiver operating characteristic (ROC)
curve with the level of LDL-Cr at 160 mg/dl for LDL-Cnf and LDL-Cf. (0.94 vs. 0.93; p=0.27).
Conclusion: There is high concordance between LDL-Cf and LDL-Cnf. These formulae could be an alternative when
there are limitations to determine LDL-C because of the lack of enzymatic methods or through Friedewald formula due to
the absence of HDL-C. Introducción: Aunque los niveles de colesterol de lipoproteínas de baja densidad (LDL-C) deben ser determinados
idealmente por betacuantificación o métodos enzimáticos, hay limitaciones en países en vía de desarrollo. El objetivo de este
estudio es comparar LDL-C obtenido a través de tres fórmulas (LDL-Cnf) con LDL-C obtenido a través de la fórmula de
Friedewald (LDL-Cf) usando LDL-C (LDL-Cr) enzimático considerado como referente más aceptado clínicamente.
Métodos: Se realizó un estudio de pruebas diagnósticas en un laboratorio de referencia en Cali, Colombia. Las tres
fórmulas fueron (mg/dl): Hombres con triglicéridos menores de 400 mg/dl: LDL-C= Colesterol total (CT) - triglicéridos (TG)/
6.5)- 45; hombres con triglicéridos iguales a o mayores de 400 mg/dl: LDL-C= (CT- (TG/7))- 50 y mujeres: LDL-C= (CT-
(TG/6.5))- 70.
Resultados: Se obtuvieron 315 valores de los cuales 53% eran mujeres. El promedio de edad y LDL-Cr fueron 54 años
(±15.8) y 112.1 mg/dl (±32.5), respectivamente. La mediana (rango intercuartil) de CT, lipoproteínas de alta densidad (HDL- C) y TG fueron de 204 mg/dl (171-229), 51 mg/dl (41-61) y
156 mg/dl (99-237), respectivamente. No hubo diferencia en
los valores promedio de LDL-Cr y LDL-Cnf (113.48 vs.
112.67 mg/dl; p=0.45). Los coeficientes de correlación
intraclase entre LDL-Cr y LDL-Cf y LDL-Cnf fueron altos
(r=0.93 y 0.92, respectivamente). La correlación entre LDLCf
y LDL-Cnf fue de 0.95. No hubo diferencias en las áreas
bajo la curvas de características operativas del receptor
(COR) con niveles de LDL-Cr de 160 mg/dl (0.94 vs. 093;
p=0.27).
Conclusión: Existe una alta correlación entre LDL-Cf y
LDL-Cnf. Estas formulas podrían ser una alternativa cuando
existen limitaciones para determinar el LDL-C.
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