OCAT (Low-dOse CT for Appendicitis Trial)
- Conditions
- Diseases of the digestive system
- Registration Number
- KCT0001953
- Lead Sponsor
- Seoul National University Bundang Hospital
- Brief Summary
Background Computed tomography (CT) radiation is arguably carcinogenic. Single-center studies, mostly retrospective, have advocated lowering the CT radiation dose for the diagnosis of appendicitis. However, the adoption of low-dose CT (LDCT) is slow. The effectiveness of LDCT compared to standard-dose CT (SDCT) has not been studied in a pragmatic multicenter setting. This was the aim of LOCAT. Methods This pragmatic, multicenter, assessor and patient blinded, parallel-group, non-inferiority, randomized trial was done at 20 Korean teaching hospitals with predominantly limited experience in LDCT. We randomly assigned (1:1) patients aged 15–44 years with suspected appendicitis to LDCT (2 mSv) or SDCT (8 mSv or lower) group by opening concealed envelopes containing site-stratified random assignments during the CT examination. The primary endpoint was negative (unnecessary) appendectomy rate among all appendectomies, analyzed by intention to treat (non-inferiority margin 4·5%). A key secondary endpoint was appendiceal perforation rate among all confirmed appendicitis cases (non-inferiority margin 10·0%). LOCAT is registered with ClinicalTrials.gov, number NCT01925014. Findings From Dec 4, 2013 through Aug 18, 2016, 1535 and 1539 patients were assigned to the LDCT and SDCT groups, respectively. The median dose-length product in each group was 132 mGy·cm (IQR 119-151) versus 486 mGy·cm (390-561). The two groups involved virtually the same care providers, including 161 radiologists, two-thirds of whom had limited LDCT experience. The negative appendectomy rate (LDCT group versus SDCT group) was 3·9% (22 of 559 patients) versus 2·7% (16 of 601) (difference 1·3%, 95% CI -0·8-3·3). The appendiceal perforation rate was 34·7% (182 of 524 patients) versus 31·2% (176 of 564) (difference 3·5%, 95% CI -2·1-9·1). Interpretation Radiation dose of appendiceal CT for adolescents and young adults can be reduced to 2 mSv without impairing clinical outcomes.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Completed
- Sex
- All
- Target Recruitment
- 3000
Participants must fulfill all of the following criteria:
•15-44 years of age.
•Emergency department visit with suspected symptoms and signs of acute appendicitis.
•Intravenous contrast-enhanced computed tomography examination*† requested due to suspicion of appendicitis.
•Willing to provide telephone or cell phone numbers for follow-up.
•Signed informed consent provided prior to study entry.
*Patients will generally be recommended to undergo ultrasonography instead of CT if they have slender body shape (body mass index less than 18.5 kg/m²), prior history of allergy to iodinated intravenous contrast materials, or prior history of renal insufficiency, although none of these are not an absolute exclusion criterion.
†Negative pregnancy status should be confirmed before CT examination in all female patients of child-bearing potential as required by the standard-of-care at each Site. Patients deemed pregnant will undergo ultrasonography and/or magnetic resonance imaging instead of CT.
Participants must not have any of the following criteria:
•Prior cross-sectional imaging tests to evaluate the presenting symptoms and signs.
•Prior history of surgical removal of the appendix.
Study & Design
- Study Type
- Interventional Study
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method egative appendectomy rate
- Secondary Outcome Measures
Name Time Method The percentage of perforated appendicitis of all confirmed appendicitis cases.;The percentage of negative appendectomies out of all randomized cases; The percentage (i.e., prevalence) of perforated appendicitis out of all randomized cases; The percentage (i.e., prevalence) of non-perforated appendicitis out of all randomized cases;The proportion of participants requiring additional imaging test(s) to diagnose or rule out appendicitis;Delay in patient disposition;Hospital stay associated with nonincidental appendectomy;The percentage of nonincidental appendectomies out of all randomized cases;Diagnostic performance of CT reports;Diagnostic confidence in diagnosing and ruling out appendicitis;Diagnosis of appendiceal perforation at CT