A-041 Contrasting Associations of Standardized Fat-to-Muscle Ratio With APRI and BARD in Korean Adults From KNHANES 2008–2009

Abstract Background Fat-to-Muscle Ratio (FMR) is emerging as an integrated index of adiposity and muscle mass, both key contributors to metabolic health. However, noninvasive hepatic fibrosis markers may respond differently to body composition. We sought to determine how a one-standard-deviation (1-SD) increase in FMR (FMR_z) relates to two fibrosis indices: (1) the AST-to-Platelet Ratio Index (APRI) using a threshold of 1 to indicate risk, and (2) the BMI-AST/ALT-Diabetes (BARD) score using a threshold of 2 to indicate risk, in a representative sample of Korean adults. Methods We analyzed cross-sectional data on 3,394 participants (19 years or older) from the Korea National Health and Nutrition Examination Survey (2008–2009), all with valid DEXA measures. FMR was standardized (FMR_z), and logistic regression models predicted: (a) an APRI value of 1 or more, and (b) a BARD score of 2 or more, from FMR_z, age, and diabetic status (normal, impaired fasting glucose, or type 2 diabetes). The APRI threshold of 1 often reflects advanced fibrosis risk, whereas the BARD threshold of 2 incorporates BMI of 28 or higher, an AST/ALT ratio of 0.8 or higher, and diabetes. Results Higher FMR_z significantly decreased the odds of having an APRI value of 1 or more (odds ratio 0.428, 95% confidence interval 0.285–0.621, p<0.0001), whereas the same 1-SD increment in FMR increased the odds of having a BARD score of 2 or more (odds ratio 2.25, 1.93–2.64, p<0.0001). Type 2 diabetes strongly affected both models, particularly the BARD score—likely reflecting partial collinearity due to the diabetes component in that calculation. Age was borderline significant in the APRI model (p=0.0646) and nonsignificant in the BARD model. Conclusion These findings highlight markedly divergent patterns between standardized FMR and two distinct noninvasive indices of hepatic fibrosis. While a higher FMR (by 1 SD) is linked to a lower APRI-based risk, it corresponds to a substantially higher BARD-based risk, probably reflecting inherent differences in how these scores integrate anthropometric and biochemical parameters. Recognizing such variability underscores the need for nuanced interpretation of hepatic assessment tools, especially in populations with altered body composition. Further research is warranted to clarify mechanisms and to examine longitudinal outcomes of interventions targeting both fat and muscle mass.