Analysis of the seasonality of care in an emergency care unit in a municipality in the interior of Paraná

Abstract

Introduction: Understanding the actual demand for a health service is fundamental for planning public health policies. A quantitative analysis of the seasonality of demand for care at an Emergency Care Unit (UPA) was conducted in a municipality with 10,233 inhabitants located 70 km from Curitiba. Objective: To stratify demand and identify seasonal patterns of visits to an Emergency Care Unit throughout the year in order to detect potential stress factors within the system. Methods: A quantitative and descriptive approach to service demand was performed, followed by normality analysis of the total number of visits using the Shapiro–Wilk and D’Agostino–Pearson tests. Weekly distribution was analyzed using the STL method, and autocorrelation was assessed through ACF and PACF. Results: Daily demand showed high variability and a structured temporal pattern. A significant difference was observed between days of the week, with a peak on Mondays and lower volume on Sundays. Daytime hours accounted for approximately 73% of visits, driving daily variability. Temporal analysis identified exclusively weekly seasonality, with persistence of this pattern across consecutive weeks. No annual seasonality was detected; monthly variation showed irregular fluctuations and clustering of high-demand days. Conclusion: Higher demand was observed at the beginning of the week, possibly reflecting reduced availability of primary care services on weekends. Additionally, lower utilization rates were observed during major national holidays throughout the year.