Ecological time-series study using secondary databases.

A time-series study will be conducted to evaluate nonattendance over time. The unit of analysis will be the appointment.

Inclusion Criteria:

• Appointments scheduled for outpatient medical care across all settings and specialties from January 1, 2016, to December 31, 2023

Exclusion Criteria:

• Cancelled appointments, including cancellations made by the patient, medical team, and the appointment management system.
• Appointments that do not correspond to scheduled in-person care (Teleconsultations,
• Appointments for walk-in demand).
• Scheduled appointments that are not for medical care (Health coverage or specialties that do not correspond to scheduled medical care, Appointments for procedures,
• Appointments for complementary exams, Appointments for treatments such as speech therapy, physiotherapy, or other therapies).
• Spontaneous overflow appointments where the patient spontaneously presents for care at that moment. These appointments cannot be absent as the present and the appointment are assigned simultaneously.
• System errors that do not correspond to actual patient medical care appointments (Duplicate cancellations, Appointments where patient and physician coincide).

The study population comprises individuals who requested at least one appointment for scheduled outpatient medical care at Hospital Italiano de Buenos Aires during the study period in any of its settings.