Study of Tomography Of Nephrolithiasis Evaluation (STONE): methodology, approach and rationale.
BACKGROUND
Urolithiasis (kidney stones) is a common reason for Emergency Department (ED) visits, accounting for nearly 1% of all visits in the United States. Computed tomography (CT) has become the most common imaging test for these patients but there are few comparative effectiveness data to support its use in comparison to ultrasound. This paper describes the rationale and methods of STONE (Study of Tomography Of Nephrolithiasis Evaluation), a pragmatic randomized comparative effectiveness trial comparing different imaging strategies for patients with suspected urolithiasis.


METHODS
STONE is a multi-center, non-blinded pragmatic randomized comparative effectiveness trial of patients between ages 18 and 75 with suspected nephrolithiasis seen in an ED setting. Patients were randomized to one of three initial imaging examinations: point-of-care ultrasound, ultrasound performed by a radiologist or CT. Participants then received diagnosis and treatment per usual care. The primary aim is to compare the rate of severe SAEs (Serious Adverse Events) between the three arms. In addition, a broad range of secondary outcomes was assessed at baseline and regularly for six months post-baseline using phone, email and mail questionnaires.


RESULTS
Excluding 17 patients who withdrew after randomization, a total of 2759 patients were randomized and completed a baseline questionnaire (n=908, 893 and 958 in the point-of-care ultrasound, radiology ultrasound and radiology CT arms, respectively). Follow-up is complete, and full or partial outcomes were assessed on over 90% of participants.


CONCLUSIONS
The detailed methodology of STONE will provide a roadmap for comparative effectiveness studies of diagnostic imaging conducted in an ED setting.
University of California, San Francisco, 533 Parnassus Ave. Ste. U368, San Francisco, CA 94143-0628, United States. Electronic address: victoria.valencia@ucsf.edu.
Victoria
V
Valencia
University of California, San Francisco, 533 Parnassus Ave. Ste. U368, San Francisco, CA 94143-0628, United States. Electronic address: michelle.moghadassi@ucsf.edu.
Michelle
M
Moghadassi
California Pacific Medical Center Research Institute, 185 Berry St., Lobby 5, Ste 5700, San Francisco, CA 94107, United States. Electronic address: dkriesel@sfcc-cpmc.net.
Dana R
DR
Kriesel
California Pacific Medical Center Research Institute, 185 Berry St., Lobby 5, Ste 5700, San Francisco, CA 94107, United States. Electronic address: SCummings@sfcc-cpmc.net.
Steve
S
Cummings
University of California, San Francisco, 350 Parnassus Ave. Ste. 307, San Francisco, CA 94143, United States. Electronic address: rebecca.smith-bindman@ucsf.edu.
Rebecca
R
Smith-Bindman
D000293:Adolescent; D000328:Adult; D000368:Aged; D057186:Comparative Effectiveness Research; D003362:Cost-Benefit Analysis; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging* / Q000191:economics; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D012107:Research Design; D012959:Socioeconomic Factors; D014057:Tomography, X-Ray Computed / Q000009:adverse effects* / Q000191:economics; D014463:Ultrasonography / Q000009:adverse effects* / Q000191:economics; D014481:United States; D055815:Young Adult
Comparative effectiveness; Computed tomography; Emergency medicine; Medical imaging; Randomized; Ultrasound