Association Between Controlled Attenuation Parameter and Mortality in Patients with Nonviral, Nonautoimmune Chronic Liver Disease

Background/Objectives: Controlled attenuation parameter (CAP) is widely used as a noninvasive marker of hepatic steatosis, but its prognostic significance in nonviral chronic liver disease is unclear. We evaluated the association of CAP with all-cause mortality and its relationship with liver stiffness measurement (LSM) and metabolic factors. Methods: We retrospectively analyzed 1040 patients with nonviral chronic liver disease who underwent FibroScan assessment in 2022 and were followed through April 2025. Cox proportional hazards models were used to identify factors associated with all-cause mortality. CAP and body mass index (BMI) were evaluated in separate primary multivariable models, with an additional exploratory model including both variables. Results: During a median follow-up of 2.8 years, 44 deaths occurred. In a multivariable model adjusted for age, sex, serum albumin, and LSM, lower CAP was independently associated with mortality (HR per 10 dB/m increase, 0.93; 95% CI, 0.89–0.98; p = 0.003), together with lower serum albumin and male sex, whereas LSM was not significant. In an exploratory model including both CAP and BMI, the association between CAP and mortality was no longer statistically significant, whereas BMI remained independently associated with mortality. Overall survival differed significantly across CAP quartiles (log-rank p < 0.001), with the lowest CAP quartile showing the poorest survival. Conclusions: Lower CAP values were associated with increased all-cause mortality; however, this association was no longer statistically significant when BMI was included in the exploratory model. Low CAP should therefore not be interpreted as a favorable phenotype without considering body composition and nutritional status. Further studies incorporating direct measures of sarcopenia and frailty are warranted.