Material and Method: All medical records in adolescent clinic at Siriraj Hospital between 2004 and 2009 were reviewed. Patients that visited the clinic at least twice with the follow-up visit order were recruited. Data analyses were performed by Chi-square test and Fisher’s exact test wherever appropriated.

Results: One hundred twenty six patients met the inclusion criteria. Patients’ mean age were 14.3-year-old (SD = 2.7) and the majority (95%) were students. Seventy one point five percent of principle diagnosis related to behavioral problems while 90% had at least one risky behavior detected. Comparing between missed and non-missed appointment, only the acute illness and the history of appointment cancellation were significant different characters between groups (p<0.001). Of 429 visits, 409 (95.3%) got telephone reminder a few days prior the appointment date, 48 (11.2%) remained non-complying and 40 (9.7%) had rescheduled. Only 18 (4.2%) of the visits were the patients themselves made re-appointments, which all complied with the new visit. Having rescheduled after being reminded and having history of a missed previous appointment were the most significant predictors for next appointment adherence (p = 0.01 and p = 0.02 respectively).

Conclusion: In adolescents, appointment non-compliance is a challenging issue for clinicians. Predicting factors found in this study might help foster appointment adherence. Interestingly, services provided such as telephone reminder, short waiting time, appointment time did not influence adherence in this population.

Keywords: Outpatient, Missed appointments, Adolescents, Appointment adherence, Appointment, Compliance