Conicity index helps predict kidney stone disease in patients with obesity: Study

A recent study has showed the link between abdominal obesity and kidney stone disease (KSD) by highlighting the significance of the conicity index to predict both KSD and all-cause mortality. The findings of this study was published in the recent issue of Nature Scientific Reports.

The conicity index is derived from waist circumference, height, and weight, making it a more focused indicator of central obesity when compared to traditional metrics like Body Mass Index (BMI). Despite its potential, this index has been relatively under-researched. The study employed logistic regression and Cox proportional hazards models to uncover its predictive power, with results suggesting a robust association between a higher conicity index and elevated health risks.

This extensive research analyzed data from 59,842 participants of the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. For every 0.1-unit increase in the conicity index, the odds of developing KSD rose by 23% (OR: 1.23, 95% CI: 1.14–1.35). The study also demonstrated that the conicity index offered a higher predictive ability for KSD when compared to conventional measures, with an area under the curve (AUC) of 0.619. This emphasizes the utility of index as a more reliable tool for identifying individuals at risk.

The findings of this study extended beyond KSD diagnosis to mortality risks. In individuals with KSD, a 0.1-unit increase in the conicity index was linked to a 44% higher risk of all-cause mortality (HR: 1.44, 95% CI: 1.14–1.82). Among participants without KSD, the mortality risk rose by 53% (HR: 1.53, 95% CI: 1.37–1.70) for the same conicity index increase.

Also, serum albumin levels and Red Cell Distribution Width (RDW) partially mediated these associations by suggesting that systemic inflammation and nutritional status play roles in these outcomes. These insights illuminate the importance of addressing central obesity as a modifiable risk factor to reduce the burden of KSD and mortality.

These results highlight the urgent need for elevated awareness of abdominal obesity and its health implications. Public health initiatives focusing on central obesity reduction could lead to significant improvements in outcomes for at-risk populations. Overall, these outcomes advocate incorporating the conicity index into routine clinical evaluations to better identify individuals at elevated risk.

Reference:

Dai, X., Chang, Y., & Hou, Y. (2025). Associations between the conicity index and kidney stone disease prevalence and mortality in American adults. In Scientific Reports (Vol. 15, Issue 1). Springer Science and Business Media LLC. https://doi.org/10.1038/s41598-025-85292-9