Background: Liver fibrosis (LF) is a serious complication of chronic liver disease that may progress to cirrhosis and liver cancer, posing a daunting threat to human health. Cardiometabolic Index (CMI) is closely associated with metabolic disorders related to obesity, which may be implicated in the pathological process of liver disease by inducing oxidative stress. However, previous observational studies have reached inconsistent conclusions on the association between CMI and hepatic fibrosis. This study aimed to assess the association of CMI and LF with oxidative stress by utilizing a population-based study.

Methods: A total of 3170 participants from the National Health and Nutrition Examination Survey (2017-2020) were included. A weighted logistics regression model was generated to analyze the correlation between CMI and LF, followed by the construction of the restricted cubic spline (RCS) model to explore the potential nonlinear relationship between the 2. In addition, the potential mediating role of oxidative stress factors (serum albumin, uric acid, γ-glutamyl transferase [GGT]) in the association of CMI with hepatic fibrosis was further investigated by regression analysis.

Results: With confounding factors adjusted, CMI was found to be associated with an increased risk of LF (odds ratio [OR] = 2.27, P < .001, 95% CI: 1.60-3.23). The stratification results showed that compared with the first quartile range, the LF risk of the second and third quartile ranges increased by 3.08 times (OR = 3.08, P < .001, 95% CI: 1.90-4.98) and 6.43 times (OR = 6.43, P < .001, 95% CI: 3.84-10.75), respectively. Further RCS analysis suggested that this association had nonlinear characteristics (P-nonlinear < .0001). Mediation analysis demonstrated that the intermediate proportions of serum albumin, uric acid, and GGT in the impact of CMI on LF were approximately 8.04%, 8.15%, and 5.60%, respectively.

Conclusion: This study demonstrated a significant positive linkage between CMI and LF, highlighting the mediating role of oxidative stress factors (serum albumin, uric acid, and GGT) in this linkage.