Non-urgent emergency department utilization in adults: a systematic review of associated factors across diverse health systems

Abstract

Non-urgent emergency department (ED) visits represent a growing global challenge with significant economic and operational consequences. Despite previous reviews, important gaps remain. No review has included all commonly used terms for non-urgent ED visits, recent evidence has not been synthesised, and factors related to patients, health systems, and care contexts have rarely been examined together. This systematic review aimed to identify and categorize factors associated with non-urgent ED visits in adults. A systematic search was conducted in PubMed, Scopus, and Web of Science for articles published between January 2015 and May 2026. We included cross-sectional, cohort, and case-control studies that compared urgent and non-urgent ED visits and reported at least one associated factor. Quality assessment was performed using Joanna Briggs Institute (JBI) checklists. Because of substantial heterogeneity in definitions, the findings were synthesised narratively. Thirty-two studies from 21 countries were included. The proportion of non-urgent visits ranged from 1% to 82.4%, depending on the definition and measurement approach used. Five approaches were used to define non-urgent visits. The most common were triage-based (41%) and clinical judgment-based (28%). Associated factors were classified into three main categories: (1) demographic and socioeconomic (younger age, female sex, low income, lower education, non-native nationality); (2) access and health system (self-referral, arrival on foot, weekend visits, shorter distance to ED, lack of a family physician, public insurance); and (3) clinical and perceptual (non-specific diagnosis, musculoskeletal problems, mental health conditions, prior ED visit history, and patient perception of illness severity). The strongest associations were reported for frequent previous ED visits (aOR up to 82.13) and patients who perceived their illness as non-serious (aOR up to 21.03). Non-urgent ED visits are influenced by multiple individual, health system, and perceptual factors. The substantial heterogeneity in definitional approaches underscores the need for conceptual standardization. No single intervention is likely to reduce non-urgent ED visits. Effective strategies should strengthen primary care, improve insurance policies, increase public health education, and empower patients.