LO86: Overutilization of computed tomography as a first-line investigation for patients presenting with suspected recurrent nephrolithiasis in the emergency department: a retrospective cohort study

Abstract

Introduction: Computed tomography (CT) has increasingly been used as a standard initial investigation for patients presenting to the Emergency Department (ED) with suspected nephrolithiasis. Compared to ultrasound, CT has increased system-level costs, ionizing radiation exposure and frequently does not alter management. For these reasons, Choosing Wisely (CW) recommends avoiding CT imaging of otherwise healthy patients younger than age 50 years presenting with symptoms of uncomplicated renal colic that have a known history of nephrolithiasis or ureterolithiasis. We aimed to evaluate the degree of utilization of CT imaging for this subgroup of patients in a tertiary care centre ED. Methods: A retrospective chart review was performed for all patients younger than 50 years who visited Sunnybrook Health Sciences Centre ED for six months between December 2015 and May 2016 with renal colic symptoms and a history of nephrolithiasis. Demographic data, relevant past medical history, clinical presentation, lab values, urology consultation, ED treatments administered, diagnostic imaging orders and dispositions were recorded for each eligible patient. Results: Out of 130 reviewed patient charts, 73 patients were identified with a previous history of nephrolithiasis and a presentation consistent with uncomplicated renal colic. 54 patients received ultrasound, KUB x-ray, or no imaging. The other 19 (26.0%) of these patients received an abdominal/pelvic CT with an indication of looking for renal or ureteral stones. Of the patients that received CT, none demonstrated significant findings warranting hospital admission or leading to identifiable changes in ED management. Five (26.3%) of these 19 patients had received a total of three to four CTs for renal colic during past Sunnybrook ED visits, while one had previously received 13 CTs. Conclusion: CT scans are often used as an initial diagnostic modality for suspected renal colic despite a Choosing Wisely recommendation to restrict the use of CT scans in a target population and infrequent changes in management after obtaining a CT. These findings highlight the need for quality improvement strategies to decrease CT utilization in this patient population with suspected renal colic.