The following is a summary of “CT Use Reduction In Ostensive Ureteral Stone (CURIOUS),” published in the May 2023 issue of Emergency Medicine by Durant et al.
Over 90% of patients diagnosed with ureteral stones undergo computed tomography (CT). Still, only 10% of patients presenting to the emergency department (ED) with acute flank pain are hospitalized for a clinically significant stone or non-stone diagnosis. Hydronephrosis can be accurately diagnosed with point-of-care ultrasound and is a crucial predictor of ureteral stone formation and subsequent complications. The absence of hydronephrosis is insufficient to rule out the presence of a stone. The researchers developed a sensitive clinical decision rule to predict ureteral stones with clinical significance. They hypothesized that this rule could identify patients with a low likelihood of experiencing this outcome. They conducted a retrospective cohort study on a random sample of 4,000 individuals who presented to one of 21 Kaiser Permanente Northern California EDs and underwent a CT for a suspected ureteral stone between January 1, 2016, and December 31, 2020.
The primary outcome was the clinically significant stone, as defined by hospitalization or urologic procedure within 60 days. Using recursive partition analysis, researchers generated a clinical decision rule capable of predicting the outcome. Based on a risk threshold of 2%, they estimated the C-statistic (area under the curve), displayed the receiver operating characteristic (ROC) curve for the model, and calculated the model’s sensitivity, specificity, and predictive values. About 354 out of 4,000 patients (8.9%) had a clinically significant stone. Their partitioning model generated four terminal nodes with varying levels of risk, ranging from 0.4% to 21.8%. The area under the ROC curve was 0.81 (95% CI: 0.80 to 0.83).
A clinical decision tree that included hydronephrosis, hematuria, and a history of prior stones predicted complicated stones with a sensitivity of 95.5% (95% CI 92.8%–97.4%), specificity of 59.9% (95% CI 58.3%–61.5%), positive predictive value of 18.8% (95% CI 18.1%–19.5%), and negative predictive value of 99.3% (95% CI 98.8%–99.6%). This clinical decision rule applied to imaging decisions would have resulted in 63% fewer CT scans with a 0.4% failure rate. Their decision rule could only be used for patients who underwent CT for a suspected ureteral stone. Consequently, this criterion would not apply to patients suspected of having ureteral colic but did not receive a CT scan because ultrasound or history was sufficient for diagnosis. These findings could serve as a foundation for future prospective validation investigations.
Source: sciencedirect.com/science/article/abs/pii/S0735675723000943