RELIABILITY FACTORS FOR THE MEASUREMENT OF HEPATIC STEATOSIS BY MEANS OF A CONTROLLED ATTENUATION PARAMETER BY TRANSIENT ELASTOGRAPHY

Abstract

The controlled attenuation parameter (CAP) allows the indirect measurement of liver fat and the indirect the indirect measurement of liver fat and stiffness by transient elastography. Its diagnostic utility has been validated, but the factors for its reliability are unknown. Therefore, the objective is to evaluate the predictors of CAP quality by transient elastography. Retrospective, observational design of transient elastography studies from January 2015 to December 2019 for fatty liver screening, fibrosis evaluation and esophageal varices screening, using Fibroscan 502 Touch with M and XL probes according to the manufacturer's recommendations. Sociodemographic and clinical data and reliability measures were evaluated: degree of liver stiffness (kpa), decibels / meter (db/m), interquartile ranges (IQR <40 and IQR <30), number of total and valid measurements. The data are shown in measures of central tendency and dispersion; for the reliability factors, a univariate and multivariate logistic regression analysis was performed. 1153 studies were analyzed, 52.6% (n = 606) were men, with a median age of 54 years [IQR 44-63] and BMI 27.4 kg / m2 [IQR 24.1-29.7]. The main indication was fatty liver screening 48.8% (n = 558), the median CAP was 262 (215-313) db / m with an interquartile range of 34 (24-47). In 26.2% (n = 302) an incorrect probe was used. The factors associated with reliability with IQR <40 were the XL probe (OR 0.34 CI95% 0.26-0.45), age <54 years (OR 0.71 CI95% 0.55-0.92) and IQR kPa <30 (OR 0.48 CI95% 0.28-0.82) and for the reliability of IQR <30 the use of the XL probe (OR 0.31 CI95% 0.23-0.42) and IQR kPa <30 (OR 0.35 CI95% 0.17-0.71). Evaluating only screening studies (n = 558), the use of the XL probe and age <54 years maintained an independent association for IQR <40 and with respect to IQR <30, only the XL probe maintained this association. Table 1. Current recommendations for quality CAP studies are to obtain valid measurements with IQR <30 and <40, although there is little evidence to support this. It was demonstrated that regardless of the indication, degree of fibrosis and BMI, the use of the XL probe favors the quality of the study and an adequate evaluation of liver stiffness (IQR kPa <30). The main factor that favors the reliability of the CAP IQR <40 and 30 is the use of the XL probe regardless of the indication for use and the body mass index. The authors declare that there is no conflict of interest.