A nomogram to predict "pure" vs. "mixed" uric acid urinary stones

Area of Science:

• Nephrology
• Urology
• Medical Imaging

Background:

• Uric acid stones (UAS) are treatable with oral chemolysis.
• Identifying patients with pure UAS is crucial for effective treatment.
• Differentiating pure from mixed UAS is essential for treatment planning.

Purpose of the Study:

• To develop a predictive nomogram for differentiating pure UAS from mixed UAS.
• To identify key clinical and imaging features associated with pure UAS.
• To aid in selecting appropriate patients for oral chemolysis therapy.

Main Methods:

• Retrospective analysis of 135 patients with predominant UAS (≥50% UA).
• Inclusion of demographic, clinical, and stone composition data.
• Development of a nomogram using logistic regression and ROC curve analysis.

Main Results:

• 62.2% of patients had pure UAS (≥95% UA), 37.8% had mixed UAS (50-90% UA).
• Pure UAS group showed significantly lower stone density (450 HU vs. 600 HU) and radiopacity (24% vs. 58%).
• Predictive factors for pure UAS included lower stone density, larger size, decreased opacity, and older age (AUC=0.78).

Conclusions:

• Imaging and demographic data can effectively identify patients with pure UAS.
• The developed nomogram can assist in patient counseling for oral chemolysis.
• Further validation of the nomogram in diverse datasets is recommended.