Risk factors and nomogram for gallbladder stones in patients with type 2 diabetes mellitus: a retrospective study...

To investigate factors associated with gallstone occurrence in patients with type 2 diabetes and to establish a nomogram for predicting gallstone presence in this population, aiming to support early risk stratification and prevention-oriented management.

This retrospective study enrolled consecutive patients who visited the Hepatobiliary Surgery and Endocrinology departments from September 2023 to December 2024. Clinical data were collected via electronic medical records. After eligibility assessment and data collection, the dataset was divided chronologically into a training cohort (September 2023 to August 2024) and an internal temporal validation cohort (September to December 2024), both from the same institution. The model was developed in the training cohort and evaluated in the training and internal temporal validation cohorts using the area under the receiver operating characteristic curve (AUC), Brier score, calibration curves, calibration intercept, calibration slope, and decision curve analysis (DCA).

After LASSO and multivariable logistic regression analyses, age, hypertension, fasting blood glucose, triglycerides, very low-density lipoprotein cholesterol (VLDL-C), and apolipoprotein A1 (ApoA1) were retained in the final model. The model showed moderate discrimination, with AUCs of 0.713 (95% bootstrap CI 0.669-0.758) in the training cohort and 0.707 (95% bootstrap CI 0.630-0.781) in the internal temporal validation cohort. The corresponding Brier scores were 0.166 and 0.180. Calibration intercepts were 0.000 and -0.063, and calibration slopes were 1.000 and 0.872, respectively. Calibration curves and decision curve analyses were also examined.

Patient age, hypertension, fasting blood glucose, triglycerides, VLDL-C, and ApoA1 were identified as predictors of gallstone occurrence in patients with type 2 diabetes. The nomogram showed moderate discrimination and may support risk stratification in this population, but its clinical utility requires external validation.