Validation of cutoffs for skeletal muscle mass index based on computed tomography analysis against dual energy X-ray absorptiometry in patients with cirrhosis: the KIRRHOS study

Abstract

Background Accurate assessments of muscle mass in patients with cirrhosis are necessary in clinical practice. Computed tomography (CT) of the upper abdomen has been proposed as a useful method for quantifying muscle mass. Recently, Carey et al developed specific cutoffs for muscle wasting based on the skeletal muscle index at the L3 vertebra (L3-SMI) for cirrhotic patients. The aim of the present study was to assess the concurrent validity of the newly proposed cutoffs of Carey et al, along with others widely used in several clinical contexts, using dual energy X-ray absorptiometry (DXA) as the reference method. Methods Data were evaluated from 97 Caucasian patients (59.8% male, 59.1±11.6 years old, 45.4% decompensated) with cirrhosis of various etiologies. Muscle mass was assessed using the appendicular lean mass index (ALMI) by DXA and the L3-SMI by CT. Low L3-SMI was defined in relation to 5 different cutoffs. Results Low muscle mass prevalence was 13.4% according to ALMI and 26.8-45.4% according to the different cutoffs applied for L3-SMI. The Carey et al, Prado et al and Montano-Loza et al cutoffs showed similar sensitivity (all 69.2%) and specificity (79.8%, 76.2% and 75.0%, respectively) and high accuracy (78.4%, 75.3% and 74.2%). The Carey et al cutoffs showed the highest diagnostic validity against DXA: the multivariate odds ratio adjusted for age, sex, body mass index category, disease etiology and model for end-stage liver disease score (95% confidence interval) was 5.88 (1.36-25.4), P=0.018. Conclusion Compared to DXA, the cutoffs for identifying muscle wasting proposed by Carey et al were proven to be the most accurate.

Optimal Skeletal Muscle Mass Index Cut-Off Values for Presarcopenia Evaluated by Computed Tomography against Dual-Energy X-ray Absorptiometry in Patients with Chronic Liver Disease

“…On the other hand, previous studies of HCC patients have shown different thresholds (men: 36.2 cm 2 /m 2 ; women: 29.26 cm 2 /m 2 ) [25]. In addition, the L3-SMI cut-off values expressed by Carey et al [26] (men: 50 cm 2 /m 2 ; women: 39 cm 2 /m 2 ) are closest to the DXA diagnosis in detecting presarcopenia in patients with cirrhosis [14]. Muscle mass is significantly reduced in severe cirrhosis; however, the influence of liver severity may have been limited in this study.…”

“…The Z-score made it possible to compare SMI by CT and ASMI by DXA. The reliability of SMI against ASMI was evaluated using Bland-Altman plots [14,20]. The normality of the mean differences between all Z-scores was examined using the Shapiro-Wilk test and presented in a histogram.…”

“…The plots show the mean differences (ASMI minus SMI in each Z-score) and the means of both Z-scores [20]. The biases and the corresponding limits of agreement (±1.96 SD) of the mean difference were calculated [14]. The cut-off values of SMI for presarcopenia using CT were calculated by receiver-operating characteristic curve (ROC) analysis with the Youden index [21].…”

“…According to these criteria, dual-energy X-ray absorptiometry (DXA) or BIA should be used for measuring SMM. SMI determined by CT and appendicular skeletal muscle mass index (ASMI; kg/m 2 ) determined by DXA have correlated in previous studies [12][13][14]. However, these studies did not focus on Asian people and did not have optimal cut-off values for SMI determined by CT. CT is often used in japan for examining patients with CLD as screening for HCC [10].…”

Muscular abnormalities in liver cirrhosis

“…They compared the success of detecting sarcopenia by DEXA and by the CT cut-off values proposed by several study groups (Carey, Montano-Loza, Mourtzakis, ESPEN, and indices proposed from oncological populations - Martin, Prado). They found that the proposed cut-off values in the DEXA-assisted analysis matched the detection of sarcopenia very well when comparing the CT cut-off values proposed by the various research groups[ 36 ]. An important finding of the study was also that the prevalence of low muscle mass did not reveal any statistically significant difference in relation to disease etiology in general.…”