Accuracy of Point-of-care Ultrasonography for Diagnosing Acute Appendicitis: A Systematic Review and Meta-analysis

Introduction The use of ultrasonography to diagnose appendicitis has become increasingly common over recent years and is well-established. More recently, point of care ultrasonography (POCUS) has also been studied for the diagnosis of appendicitis, which may also prove a valuable diagnostic tool. The purpose of this study is through systematic review and meta-analysis to identify the test characteristics of POCUS, specifically ultrasonography performed by a non-radiologist physician, in accurately diagnosing acute appendicitis in patients of any age. Methods We conducted a thorough and systematic literature search of English language articles published on point of care, physician-performed transabdominal ultrasonography used for the diagnosis of acute appendicitis from 1980 to May, 2015 using OVID® Medline, In-Process, and Other Non-indexed Citations; and SCOPUS. Studies were selected and subsequently independently abstracted by 2 trained reviewers. A random effects pooled analysis was used to construct a hierarchical summary receiver-operator characteristic curve, and a meta-regression was performed. Quality of studies was assessed using the QUADAS-2 tool. Results Our search yielded 5,792 unique studies and we included 21 of these in our final review. Prevalence of disease in this study was 29.8%, (range, 6.4%-75.4%). The sensitivity and specificity for POCUS in diagnosing appendicitis was 91% (95%CI, 83%-96%) and 97% (95%CI, 91%-99%), respectively. The positive and negative predictive values were 91% and 94%, respectively. Studies performed by emergency physicians had slightly lower test charcteristics (sensitivity=80%, specificity=92%). There was significant heterogeneity between studies (I2=99%, 95%CI, 99-100%) and the quality of the reported studies was moderate, mostly due to unclear reporting of blinding of physicians and timing of scanning and patient enrollment. Several of the studies were performed by a single operator, and the education and training of the operators was variably reported. Conclusion POCUS has a relatively high sensitivity and specificity for diagnosing acute appendicitis, though the data presented is limited by the quality of the original studies and large confidence intervals. In the hands of an experienced operator, POCUS is an appropriate initial imaging modality for diagnosing appendicitis. Based on our results, it is premature to utilize POCUS as a standalone test or to rule out appendicitis. This article is protected by copyright. All rights reserved.