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

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. 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. Four studies with 343 participants were included. The pooled sensitivity and specificity were 0.94 (95% CI (confidence interval) = 0.83-0.98; I = 79%) and 0.49 (95% CI = 0.33-0.66; I = 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. 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.