Temporal trends and patterns of pre-hospital emergency medical service utilization in Yasuj, Southwest Iran: a four-year registry-based cross-sectional study

Pre-hospital Emergency Medical Services (EMS) are essential for the timely management of traumatic injuries and acute medical emergencies. This study evaluated temporal trends, epidemiological characteristics, and utilization patterns of pre-hospital EMS missions in Yasuj, Southwest Iran, from 2020 to 2023. This registry-based cross-sectional study included all eligible EMS missions recorded in the Asayar pre-hospital EMS registry between January 2020 and December 2023. Data on patient age, mission date, season, hour of occurrence, chief complaint, mission outcome, and ambulance operational code were analyzed. Mission characteristics were summarized using descriptive statistics, and effect sizes were considered alongside statistical significance for categorical analyses. Temporal trends were evaluated using 48 monthly observations in a time-series regression model of log-transformed monthly mission counts, accounting for calendar-month seasonality and first-order autoregressive [AR(1)] errors. A total of 159,073 EMS missions were analyzed. Annual mission volume increased from 28,312 in 2020 to 58,287 in 2023, corresponding to an approximate compound annual growth rate of 27.2%. Monthly mission volume increased by an estimated 1.82% (multiplicative monthly change = 1.018; 95% CI: 1.010–1.026; p < 0.001), with no significant residual autocorrelation (Ljung–Box p = 0.623). Road traffic accidents were the leading cause of EMS activation (24.9%). Adults aged 30–39 years represented the largest age group among missions with recorded age (20.31%). EMS utilization was highest in summer and during evening hours, while cardiovascular-related complaints and carbon monoxide poisoning were more frequent in winter. Effect sizes for categorical associations were generally small. EMS utilization in Yasuj increased substantially over the study period and showed distinct temporal, seasonal, and epidemiological patterns. These findings can support data-driven EMS planning, resource allocation, seasonal preparedness, and policy development. Future studies incorporating comprehensive operational and geographic data are warranted. Not applicable.