The diagnostic performance of liver stiffness measurement (LSM) has a key role in the evaluation of fibrosis stages in patients with non-alcoholic fatty liver disease (NAFLD). Whether LSM differs between non-obese and obese NAFLD patients is not clearly known.

Patients diagnosed as NAFLD by liver biopsy according to NASH CRN scoring system were recruited in the study. Non-obese was defined as BMI <25 kg/m². LSM measurement was done by experienced physicians within 2 weeks of liver biopsy.

The study included 158 patients, 68 non-obese and 90 obese. The average BMI of non-obese and obese patients was 23.2 ± 1.6 kg/m² and 27.9 ± 2.5 kg/m², respectively. Following adjustment for age, fibrosis stage, steatosis grade and diabetes, non-obese patients reported 3.5 kPa lower LSM compared to obese patients. LSM values of non-obese patients appeared to be lower stratified by fibrosis stage, particularly in cirrhosis patients (F4). When separated cut-off was applied for non-obese vs. obese NAFLD in individual fibrosis stage, 5.8 vs.7.5 kPa (F1), 7.6 vs. 8.5 kPa (F2), 9.1 vs. 11.2 kPa (F3), and 12.5 vs. 14.3 kPa (F4), diagnostic odds ratios (DORs) were seen to improve compared to using overall cut-off values. Among non-obese NAFLD patients, making use of separated cut-off could avoid 9% cirrhosis patients being underestimated.

The study concluded that non-obese NAFLD patients had lower LSM values compared to obese patients and that separate cut-offs should be used in non-obese and obese NAFLD patients.

Source: Shi YW, Wang QY, Zhao XY, et al. Non-obese NAFLD patients may use lower liver stiffness cut-off to better assess fibrosis stages. J Dig Dis. 2020 Apr 26.