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Development and external validation of a pragmatic nomogram for point-of-care urolithiasis screening in
Banchao Shen1,2, Shuhan Yang3, Peng Wu1
1Department of Urology, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi, China.
Background:
The rising burden of urolithiasis in Southeast Asia and the lack of efficient risk-screening tools for low-resource primary care, such as those in Laos, motivated the development and external validation of a pragmatic nomogram integrating accessible environmental, behavioral, and clinical factors for in-hospital urolithiasis risk stratification, with long-term goal of application in grassroots screening.
Methods:
A retrospective study was conducted with 665 consecutive inpatients (≥18 years, local residence ≥6 months) at a Lao Military Hospital (March 2024-February 2025). Data were collected using standardized questionnaires and electronic medical records. Least Absolute Shrinkage and Selection Operator (LASSO) regression selected predictors; nomogram performance was assessed by discrimination (area under the curve (AUC)), calibration (Brier score and Hosmer-Lemeshow test), and clinical utility (decision curve analysis (DCA)).
Results:
Urolithiasis prevalence was 23.0% (153/665). Independent predictors included age (30-59 years, OR = 1.54; ≥60 years, OR = 1.13), sex (OR = 0.59), rural residence (OR = 0.52), high water intake (>1,500 mL/day, OR = 0.02), high sodium consumption (>10 g/day, OR = 21.90), and elevated blood calcium (OR = 9.12). The nomogram presented stable predictive performance, with an AUC of 0.882-0.907, Brier score of 0.086-0.111 (acceptable calibration, Hosmer-Lemeshow p = 0.198-0.892), and optimal clinical threshold at 0.20.
Conclusions:
This externally validated nomogram uses six accessible environmental, behavioral, and clinical factors to stratify urolithiasis risk in Laos. At present, it helps guide targeted referral and optimize s resource allocation for hospitalized patients in resource-limited settings, while its application in primary care and among broader Southeast Asian populations remains to be prospectively evaluated.
