Prognostic value of total body muscle-fat ratio in patients with kidney stone disease: A US population-based study.

Purpose: To examine the relationship between the muscle-fat ratio (MFR) and kidney stone disease (KSD) in the adult population of the United States between 2011 and 2018, and whether it can be used as a predictor of KSD prognosis. Materials and methods: We conducted a cross-sectional study analysing 9326 patients from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. We analyzed all participants by sex, age, race, level of education, marital status, household income-to-poverty ratio, hypertension, diabetes, vigorous physical activity, moderate physical activity, blood urea nitrogen, creatinine, uric acid, cotinine, and MFR. Dose-response curves with a restricted cubic spline function, univariate and multifactorial logistic regression were used for the analysis of the correlation between MFR and KSD. Finally, we created predictive models based on age, race, hypertension, diabetes mellitus, cotinine and MFR. The prediction model was evaluated using calibration curves, receiver operating characteristic curves and clinical decision curves from the training and test sets. Results: Of the 9326 participants, 8582 (92%) self-reported that they did not have KSD and 744 (8%) self-reported that they had KSD. Univariate and multifactorial logistic regression showed that MFR was negatively associated with the prevalence of KSD (odds ratio [OR]: 0.770, 95% CI: 0.703-0.843; OR: 0.815, 95% CI: 0.738-0.897). Similarly, the risk of developing KSD decreased with increasing MFR as shown by the dose curves in the restricted cubic bar graphs. Furthermore, there is some accuracy (AUC = 0.652) and clinical applicability to the model we constructed based on the results of multifactorial logistic regression. Conclusion: The MFR is protective factor against the developing KSD in adults in the USA.