A 5 sit-to-stand test may identify NAFLD patients at higher risk for worse clinical outcomes

Background

Non-alcoholic fatty liver disease (NAFLD) is an important cause of chronic liver disease, with cardiovascular events being the first cause of morbidity and mortality in this population. Sarcopenia has been suggested to predict worse outcomes in cirrhotic patients, however the evidence exploring its impact in non-cirrhotic NAFLD patient is scarce. This study aimed to evaluate muscle mass and function in a cohort of NAFLD patients and to identify associations with clinical phenotype and disease severity.

Methods

Consecutive patients with NAFLD were prospectively enrolled at their routine clinical appointment in the liver clinic at St Mary’s Hospital (Imperial College Healthcare NHS trust, London). Anthropometric, biochemical, and demographic parameters were collected. Transient elastography was also recorded at the day of the visit. Muscle mass was assessed using fat-free mass index (FFMI) from bioimpedance analysis (BIA). In a small subset of patients, skeletal mass index (SMI) from CT analysis, using machine learning, was calculated. Muscle strength was assessed with the 5 times sit-to-stand test (5STST) and handgrip strength test (HST). Sarcopenia was defined as per guidelines.

Results

A total of 189 patients were included. Low muscle function was found in 64 of 160 (33.9%) as per 5STST, and 41 of 182 (22.7%) as per HST. Low muscle quantity was found in 5.3% (9/169) according to FFMI and 35% (6/17) according to SMI. Patients with poor 5STST showed higher fat mass (%) (39 ±10.2 vs 33.4 ±9.3, p<0.001), lower FFMI (55.4 ±12.1 vs 61.8 ±12.1, p=0.002), lower muscle mass (kg) (52.77 ±11.56 vs 58.78 ±11.61, p=0.002) on BIA, compared to those with normal 5STST. Low SMI and FFMI were significantly associated with lower BMI (26.3 vs 32.7 kg/m2, p=0.001 and 25.6 vs 34.7 kg/m2, p=0.004 respectively). On multivariate analysis, both SMI (OR 0.734, 95%CI: 0.548–0.982, p=0.037) and FFMI (OR 0.803, 95%CI: 0.678–0.952, p=0.010) were independently associated with lower BMI. Moreover, previous history of MACE (OR 14.98, 95%CI: 2.517–89.149, p = 0.003), BMI (OR 1.079, 95%CI: 1.004–1.161, p=0.04), LSM (OR: 1.073, 95%CI 1.003–1.148, p=0.042) and male gender (OR 0.276, 95%CI: 0.117–0.65, p=0.003) were independently associated with a poor performance on 5STST. LSM was also independently associated with a poor HST (OR 1.106, 95%CI: 1.038–1.18, p = 0.002), even after adjusting for BMI.

Conclusion

Both severity of liver disease and history of cardiovascular events predict sarcopenia in patients with NAFLD. A 5 sit-to-stand test is a quick, inexpensive measurement which could assist with identifying a NAFLD phenotype who may be at higher risk for worse clinical outcomes.