Association between body mass index and liver stiffness measurement using transient elastography in patients with non-alcoholic fatty liver disease in a hepatology clinic: a cross sectional study.

Background: Transient elastography (TE) is an FDA approved, non-invasive tool to estimate liver stiffness measurement (LSM) in patients with non-alcoholic fatty liver disease (NAFLD). Our aim was to analyze if body mass index (BMI) would predict the severity of liver stiffness using TE scores.

Methods: We performed a cross-sectional study of patients with NAFLD who presented to the hepatology clinic between January 2019 through January 2021. Fibrosis severity was divided into the following categories: F0 to F1 (2-7 kPa), F2 (>7 to 10 kPa), F3 (>10 to 14 kPa) and F4 (>14 kPa). We used ordered logistic regression models to determine the odds ratio (OR) and 95% confidence interval (CI) of having a higher LSM severity compared to lower associated with BMI. Models were adjusted for patient demographics and comorbidities.

Results: Among 284 patients, 56.7% were females, and the median (interquartile range, IQR) age was 62 [51-68] years and BMI 31.9 (28.1, 36.2) kg/m²; 47% of patients were in the F0 to F1 stage, 24% F2, 16% F3, and 13% F4. The correlation between BMI and TE score was 0.31 (P<0.001). With 1 kg/m² increase in BMI there was 1.10 times higher odds of having a higher LSM severity (adjusted OR, 1.10; 95% CI: 1.05-1.14). Compared to patients with BMI <25 kg/m², the adjusted OR (95% CI) of having a higher fibrosis stage was 1.82 (0.61-5.44), 5.93 (2.05-17.13), and 8.56 (2.51-29.17) for patients with BMI of 25 to <30, 30 to <40, and ≥40 respectively.

Conclusions: BMI correlates with the severity of LSM using TE scores in NAFLD patients even after adjusting for potential confounding variables. This suggests TE as an appreciable study for liver stiffness even in obese individuals.