Association between metabolic syndrome and calcium oxalate stone risk in Chinese individuals: a nomogram prediction model

Objective This retrospective study explored the association between calcium oxalate (CaOx) stones and metabolic syndrome. It also developed and validated a nomogram to aid in the prediction of CaOx stones. Methods This case-control study enrolled 150 patients with CaOx stones and 635 individuals without urolithiasis from October 2016 to October 2018. Student's t-test, the chi-squared test, and logistic univariate and multivariate regression analyses were used. A nomogram for prediction of CaOx stones was established based on independent associated factors. The concordance index and calibration curves were plotted to determine nomogram accuracy. Results Female sex, age >= 66 years, blood pressure (systolic pressure >= 130 mmHg and/or diastolic pressure >= 85 mmHg), and blood uric acid level independently influenced the risk of CaOx stones, according to multivariate logistic regression analysis; these factors were included in the nomogram. The concordance index was 0.701 (95% confidence interval: 0.658-0.737). The standard curve showed a robust fit with the calibrated predictive curve. Conclusions Female sex, age >= 66 years, elevated blood pressure, and blood uric acid level independently influenced the risk of CaOx stones. Our nomogram for the prediction of CaOx stones may provide a clinical basis for the assessment of CaOx stone and facilitate early prevention efforts.