Short observation and rescoring separated equivocal appendicitis cases that need CT from those that do not

Design

Secondary analysis of the observation arm of a randomised trial

Population

83 adults with early equivocal signs of appendicitis

Primary outcome

Diagnostic accuracy of change in Adult Appendicitis Score

Effect

AUROC 0.93 (0.87–1.00) vs baseline score 0.63; NPV 97% (≤−2), PPV 94% (≥+1)

In the DIAMOND trial, adults with early equivocal signs of appendicitis were observed and rescored rather than scanned immediately. This secondary analysis of the 83 observed patients with complete data asked whether the change in Adult Appendicitis Score during observation could select patients for imaging.

The change in score discriminated appendicitis well (AUROC 0.93, 95% CI 0.87–1.00), much better than the baseline score (0.63) and better than the change in C-reactive protein (0.80). A change of −2 or less had a negative predictive value of 97%; a change of +1 or more had a positive predictive value of 94%. Patients with a change of −1 or 0 formed an intermediate group.

For radiologists and emergency teams, this supports a pathway in which CT is reserved for the intermediate group after a period of observation, rather than scanning every equivocal presentation on arrival. In Indian emergency departments, where CT access and radiation dose both matter, observation and rescoring is cheap. The thresholds come from one small analysis and need validating before they are hard-coded into protocols.

• Record an Adult Appendicitis Score at presentation for adults with equivocal right iliac fossa pain
• Rescore after a defined observation period rather than imaging immediately when the patient is stable
• Reserve CT for patients whose score is unchanged or has fallen by only one point
• Use ultrasound first in young women and slim patients where it is available and reliable
• Agree the observation pathway jointly with the surgical team

Why it matters

Immediate CT for every equivocal case adds radiation and overdiagnosis, and change over a few hours carries more information than a single score.

Don't overread it

The thresholds were derived in 83 patients without external validation, so they are a starting point for a local pathway, not a proven rule.

The statistics, in plain English

An AUROC of 0.93 means the score change ranks a patient with appendicitis above one without it 93% of the time. Predictive values depend on how common appendicitis is in the group being tested, so the 97% and 94% figures may not hold where prevalence differs. The thresholds were derived and tested in the same 83 patients, which tends to overstate performance.

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