The modified cardiometabolic index is associated with gallstones in US adults: a cross-sectional analysis

Gallstones are common and are associated with obesity, insulin resistance, and dyslipidemia. We examined the association between the modified cardiometabolic index (MCMI) and prevalent gallstones, compared its discriminative performance with related indices, and developed an internally evaluated model for identifying participants with gallstones. We analyzed National Health and Nutrition Examination Survey 2017 to March 2020 data. Survey-weighted multivariable logistic regression, restricted cubic splines, subgroup analyses, and receiver operating characteristic curves were used to assess the association between MCMI and self-reported physician-diagnosed gallstones and its discrimination for prevalent gallstones. The Boruta algorithm and least absolute shrinkage and selection operator regression were used for variable selection. A nomogram was developed and internally evaluated using receiver operating characteristic, calibration, and decision curves. Higher MCMI was associated with greater odds of prevalent gallstones; each 1-unit increase corresponded to an adjusted odds ratio of 1.47 (95% confidence interval = 1.22-1.78). The association varied by age and marital status and was strongest among unmarried participants aged <40 years. MCMI showed modest discrimination (area under the curve = 0.654), exceeding the compared indices. Ten variables were retained for the nomogram. The training and test area-under-the-curve values were 0.75 and 0.77, respectively. MCMI was independently associated with self-reported physician-diagnosed gallstone prevalence and showed modest discrimination. The internally evaluated nomogram may support identification of individuals with prevalent gallstones, but prospective and external validation is required before clinical use.