Disparities and determinants of EMS response times: a mixed-methods systematic review and LDA-based thematic analysis

Abstract

Purpose – Response times of emergency medical services (EMS) are critical for patient outcomes and survival rates. This review synthesizes evidence on factors affecting EMS response times and their impacts, aiming to identify disparities and recommend optimization strategies. Design/methodology/approach – A systematic search was conducted in Web of Science, PubMed and Scopus for English-language studies published between January 1, 2000, and October 20, 2024. Inclusion criteria focused on studies examining EMS response times and associated outcomes, such as mortality and disparities. Exclusion criteria ruled out studies on non-EMS services, case reports and non-English publications. Two independent reviewers screened studies, and risk of bias was assessed using the Cochrane Risk of Bias 2 tool for randomized controlled trials and the Joanna Briggs Institute for observational studies. A narrative synthesis was performed, and meta-analysis was considered where data permitted. Findings – Of 105 initial articles, 45 studies met the inclusion criteria. Key findings identified five domains impacting EMS response times: ambulance deployment strategies, mortality correlations, optimal placement of ambulances, socioeconomic and geographic disparities and specialized service performance. Quantitative analysis demonstrated that strategic ambulance placement and addressing inequities reduced response times and improved survival rates. Research limitations/implications – This research highlights several limitations, including data limitations, challenges in addressing geographic and socioeconomic disparities and the need to overcome technological and ethical hurdles. Key research implications include fostering multidisciplinary collaboration, conducting longitudinal studies and prioritizing cost-effectiveness. Addressing inequities in access to care is paramount, requiring targeted interventions and a focus on patient-centred care. Integrating technology while ensuring data security and privacy is crucial. Finally, standardized data collection methods and a focus on continuous improvement through rigorous evaluation are essential for optimizing EMS systems globally. Originality/value – Although previous systematic reviews have analysed EMS response times and patient outcomes, these studies often fail to address the impact of socio-economic disparities and geographic isolation comprehensively. Furthermore, methodological inconsistencies, including varying definitions of response times, limit comparability across studies.