Low‐quality muscle mass rather than normal‐quality muscle mass determines fibrosis progression in biopsy‐proven NAFLD

Abstract

Summary Background and aims Sarcopaenia is associated with advanced nonalcoholic fatty liver disease (NAFLD). However, the impact of the muscle mass categorised by muscle quality on fibrosis progression remains unclear. Methods A total of 292 patients with biopsy‐proven NAFLD who underwent serial vibration‐controlled transient elastography assessments at least 1 year from baseline were selected. The skeletal muscle area (SMA) was determined on abdominal computed tomography (CT) at the third lumbar vertebra level and categorised to normal‐attenuation muscle area (NAMA), low‐attenuation muscle area (LAMA) and intermuscular adipose tissue (IMAT) using a muscle quality map. These SMAs were normalised by the height squared to obtain the skeletal muscle index (SMI). Results At baseline, as the histological fibrosis stage increased, SMINAMA decreased and SMILAMA increased (p for trend = 0.014 and p for trend <0.001, respectively), which was not significant after adjustment for age, sex and obesity. During a median follow‐up of 41 months, fibrosis progression was detected in 48 out of 292 patients, and higher SMILAMA quartiles independently increased the risk of fibrosis progression in a dose‐dependent manner (hazard ratio [HR] per quartile: 1.41; 95% confidence interval [CI], 1.04–1.91). The highest quartile of SMILAMA increased the risk of fibrosis progression by 3.25 times compared to the lowest quartile of SMILAMA (95% CI, 1.18–8.90). SMINAMA quartiles were not associated with the risk of fibrosis progression. Conclusion Increased low‐quality muscle mass, but not decreased normal‐quality muscle mass, as assessed by a muscle quality map in CT, predicts fibrosis progression in patients with NAFLD.

Editorial: Let your muscles do the talking—what can muscle quality tell us about hepatic fibrosis?

“…The prospective, observational study by Lee et al 1 supports the burgeoning idea that “muscle quality” is an early signal for fibrosis progression. Patients with biopsy‐proven NAFLD were followed up for a median of 41 months.…”

Editorial: Let your muscles do the talking—what can muscle quality tell us about hepatic fibrosis? Authors' reply

“…This article is linked to Lee et al papers. To view these articles, visit https://doi.org/10.1111/apt.17601 and https://doi.org/10.1111/ apt.17618 Yun Kyu Lee 1 Bo Kyung Koo 1,2 Won Kim 1,3…”

“…We thank Petroff et al 1 for their critical comments and discussion regarding our publication 2 . Their main concerns with our study were the possible biases introduced by the intrinsic drawback of vibration‐controlled transient elastography (VCTE) and uncertainty about the clinical utility of assessing muscle quality to identify high‐risk populations with nonalcoholic fatty liver disease (NAFLD).…”

“…Since ours was a non‐interventional observational cohort study, 2 repetitive measurements of fibrosis markers were necessary for detecting fibrosis progression during the median follow‐up of 41 months (IQR, 30–60 months). Our study 2 included 292 patients after excluding some with relatively short follow‐up.…”

“…Since ours was a non‐interventional observational cohort study, 2 repetitive measurements of fibrosis markers were necessary for detecting fibrosis progression during the median follow‐up of 41 months (IQR, 30–60 months). Our study 2 included 292 patients after excluding some with relatively short follow‐up. As we are recruiting an ongoing prospective cohort with the annual or biennial follow‐up VCTE, the effect of muscle quality on fibrosis progression will become more evident over the next few years.…”