Background: The purpose of this research was to determine the index that contributes the most to assessing the effectiveness of weight loss 1 year following bariatric surgery and to implement it as the clinical outcome to develop and confirm a nomogram to predict whether bariatric surgery would be effective. Methods: Patient information was extracted from the Chinese Obesity and Metabolic Surgery Database for this retrospective study. The most contributing weight loss effectiveness evaluation index was created using canonical correlation analysis (CCA), and the predictors were screened using logistic regression analysis. A nomogram for estimating the likelihood of effectiveness of weight loss was constructed, and its performance was further verified. Results: Information was obtained for 540 patients, including 30 variables. According to the CCA, ≥25 percentage total weight loss was found to be the most correlated with patient information and contribute the most as a weight loss effectiveness evaluation index. Logistic regression analysis and nomogram scores identified age, surgical strategy, abdominal circumference, weight loss history, and hyperlipidemia as predictors of effectiveness in weight loss. The prediction model’s discrimination, accuracy, and clinical benefit were demonstrated by the consistency index, calibration curve, and decision curve analysis. Conclusions: The authors determined a 25 percentage total weight loss as an index for weight loss effectiveness assessment by CCA and next established and validated a nomogram, which demonstrated promising performance in predicting the probability of effectiveness of weight loss in bariatric surgery. The nomogram might be a valuable tool in clinical practice.

Metabolic hyperferritinaemia (MHF) is closely linked to obesity and metabolic disorders, yet large-sample quantitative evidence regarding its clinical characteristics and multisystem metabolic correlations in morbidly obese populations remains insufficient. This study aimed to investigate the prevalence of MHF among bariatric surgery candidates and clarify its associations with liver function, glycolipid metabolism, and hematological indicators. A cross-sectional case-control study was conducted on 695 patients scheduled for bariatric surgery. Patients were stratified into MHF and normal iron groups based on gender-specific serum ferritin cut-off values. Independent-samples t-test and Wilcoxon rank-sum test were applied to compare 14 core metabolic and clinical indicators, and correlation analysis was performed to assess the association between ferritin levels and key parameters. The overall MHF prevalence was 18.51%, with a markedly higher rate in males (32.67%) than in females (10.54%) and a significant upward trend with increased BMI. The MHF group exhibited significantly abnormal liver function, glycolipid metabolism, and hematological indices. Serum ferritin showed moderate positive correlations with alanine aminotransferase and γ-glutamyl transferase. MHF is highly prevalent in patients undergoing bariatric surgery and is closely associated with systematic metabolic and hematological abnormalities. Targeted iron regulation may be a promising strategy to alleviate obesity-related metabolic complications, providing novel clinical insights for high-risk population management.