Can The ‘Speed Bump Sign’ Be a Diagnostic Tool for Acute Appendicitis? Evidence-Based Appraisal by Meta-Analysis and GRADE

Objectives: The ‘speed bump sign’ is a clinical symptom characterised by aggravated abdominal pain while driving over speed bumps. This study aimed to perform a diagnostic meta-analysis, rate the certainty of evidence (CoE) and analyse the applicability of the speed bump sign in the diagnosis of acute appendicitis. Materials and Methods: Four databanks and websites were systemically searched, and the Quality Assessment of Diagnostic Accuracy Studies 2 was used to evaluate the risk of bias. Meta-analysis was assessed by MIDAS commands in Stata 15. Grading of Recommendations, Assessment, Development and Evaluation methodology was applied to examine the CoE. Results: Four studies with 343 participants were included. The pooled sensitivity and specificity were 0.94 (95% CI (confidence interval) = 0.83–0.98; I(2) = 79%) and 0.49 (95% CI = 0.33–0.66; I(2) = 67%), respectively. The area under the summary receiver operating characteristic curve was 0.78 (95% CI = 0.74–0.81). The diagnostic odds ratio was 14.1 (95% CI = 3.6–55.7). The pooled positive and negative likelihood ratios (LR (+) and LR (−)) were 1.84 (95% CI = 1.30–2.61) and 0.13 (95% CI = 0.04–0.41), respectively. According to Fagan’s nomogram plot, when the pretest probabilities were 25%, 50% and 75%, the related posttest probabilities increased to 38%, 65% and 85% calculated through LR (+), respectively, and the posttest probabilities were 4%, 12% and 28% calculated through LR (−), respectively. The overall CoEs were low and very low in sensitivity and specificity, respectively. Conclusion: Current evidence shows that the speed bump sign is a useful ‘rule-out’ test for diagnosing acute appendicitis. With good accessibility, the speed bump sign may be added as a routine part of taking the history of patients with abdominal pain.