Temporal trends in the non-attendance to scheduled outpatient appointments

Abstract Background: Outpatient non-attendance is a frequent and relevant problem in healthcare systems, reflecting both quality of care and access equity. Despite its relevance, its temporal trends and potential variations remain understudied. Objectives: To analyze trends in non-attendance percentage for scheduled outpatient visits from 2016 to 2024 and identify significant changes overall and within subgroups. Methods: This ecological time-series study included in-person scheduled medical appointments, using secondary data from the Hospital Italiano de Buenos Aires. The study period was divided into pre-pandemic (January 2016–February 2020) and post-pandemic (January 2021–December 2024). The percentage of non-attendance was estimated for all appointments and for subgroups of sex, age, medical speciality, and healthcare payer. Joinpoint regression models are used to evaluate trends and calculate the monthly percentual change (MPC). Results: Among 15 747 265 scheduled outpatient appointments, the non-attendance percentage was 26.86% (95% CI 26.84%-26.88%). The percentage declined pre-pandemic, from 29.1% (2016) to 21.44% (2024), with a decreasing trend (MPC = -0.10; P < .01). Post-pandemic trends showed an average MPC of -0.65 (P = 0.55), with joinpoints in December 2022, May 2023, and December 2023. Subgroup trends mirrored global findings, with higher non-attendance percentages in females, surgical specialties, and private payers. The lowest percentages occurred in adults over 65. Discussion: Non-attendance varied annually, showing distinct pre- and post-pandemic patterns. Fluctuations may reflect the pandemic’s impact and broader socioeconomic factors, highlighting barriers to access and the effectiveness of the system.