Clinical decision rules for obtaining chest radiography in adult patients presenting to the emergency department with non-traumatic chest pain: a systematic review and meta-analysis

Introduction Chest pain is the second leading emergency department (ED) presentation, with its associated diagnostics requiring ED resource utilisation. Radiography is used in 70% of cases but identifies clinically significant findings in only 1.5%–2.1%. The predominance of non-actionable imaging results, combined with paucity of decision rules, prompted this systematic review to inform the development of a new clinical decision rule (CDR). Methods Four bibliographical databases were searched, including: PubMed, MEDLINE, EMBASE and COCHRANE. Study selection, extraction and quality assessment were conducted independently by two reviewers via Covidence. Studies using a shared clinical decision tool were pooled to calculate sensitivity, specificity, likelihood ratios and false-positive rates using Meta-DiSc V.2.0. Univariate and, where possible, bivariate analyses generated forest plots and summary receiver operating characteristics curves. Heterogeneity was quantified by I², and methodological bias assessed via the Prediction model study Risk of Bias Assessment Tool (PROBAST). Results From 626 records, 7 studies (6654 ED patients, Canada, Australia, USA) met inclusion. Of these, further analysis was undertaken of four validation studies. Two studies examined the Hess CDR reporting 98.3% sensitivity (95% CI 17% to 100%) and 47.6% specificity (95% CI 43.8% to 51.3%). Two studies examined the Rothrock CDR and reported 88.6% sensitivity (95% CI 80.1% to 93.7%) and 73% specificity (95% CI 17.7% to 97.2%). Hess had a negative likelihood ratio of 0.04 (95% CI 0 to 9.17) compared with Rothrock (0.156, 95% CI 0.06 to 0.38) and Rothrock had a positive likelihood ratio of 3.3 (95% CI 0.52 to 20.95) compared with Hess (1.9, 95% CI 1.67 to 2.11). Meta-analysis showed high heterogeneity with low bias as per PROBAST criteria. Conclusions A systematic review and meta-analysis of two chest X-ray decision rules for non-traumatic chest pain found the Hess et al rule more sensitive but unlikely to reduce imaging. Evidence is limited by few studies, high heterogeneity and retrospective cohorts. Neither rule is recommendable, highlighting the need for prospective derivation using established methodological standards.