Derivation of a clinical predicting rule for obstructive urolithiasis and alternative diagnosis requiring urgent intervention: the CLAD score.

Most patients with renal colic are discharged from the emergency department (ED) after evaluation and pain alleviation. These patients may not require urgent imaging by computed tomography. We derived a clinical prediction score in patients with renal colic to identify those at very low risk for complications and alternative diagnoses requiring urgent intervention. This retrospective chart review was carried out in 2 ED at an urban university hospital from January to December 2015. All patients with a diagnosis of renal colic were included. The primary outcome was an intervention required for renal colic or alternative diagnoses within 7 days of ED presentation. A stepwise logistic regression was used to assess factors associated with the outcome. A score was derived as a weighted sum of these predictors and its performance was calculated. The database was submitted to the French National Commission for Data Protection and Liberties (CNIL): declaration n°2164898v0 (03/22/2018). 871 with complete data were analyzed. In 94 (11%) patients, an intervention was performed for obstructive urolithiasis or alternative diagnosis. Five factors were most predictive of intervention: age > 45 years (1 point), a history of urologic surgery (1 point), pulse > 100 bpm (1 point), temperature > 37.8 °C (2 point), and urine dipstick negative for blood (1 point), yielding a score of 0-6 points (the Complicated uroLithiasis and Alternative Diagnosis (CLAD) score). The area under the curve of the receiver operating characteristic curve was 0.82 (95% CI 0.77-0.87). We derived a clinical score for renal colic that predicted the presence of obstructive urolithiasis and acute alternative diagnoses requiring intervention.