ABSTRACT. Objective. To determine the effect of a single telephone call reminder on appointment compliance among adolescents in an inner city, hospital-based clinic.Methods. A randomized clinical trial was conducted at the Adolescent Clinic, a part of the Ambulatory Pediatric Practice Clinic in Cleveland, Ohio, from December 1995 to November 1996. A total of 703 routine adolescent ambulatory appointments were randomized to receive either a single telephone call reminder 1 day before the appointment or to receive no reminder. A single telephone call attempt was directed primarily to the parent or guardian of the patient in the assignment group. If not available, the reminder message was left with the patient or other family member, or on the answering machine. The study variables selected included age, gender, appointment time, distance from clinic, and payment source, and for the intervention group, the recipient of the reminder telephone call. The outcome measure was the attendance rate.Results. The intervention group (n ؍ 347) and control group (n ؍ 356) were well balanced for all study variables. The overall attendance rate was 49.8%. Only 204 (58.8%) of the 347 attempted intervention appointments were contacted successfully by telephone. In the attempted intervention analysis, the attendance rate of 55.6% in the intervention group (n ؍ 347), regardless of whether subjects were successfully contacted by telephone, was 26.1% greater than the 44.1% attendance rate in the control group. In the completed intervention analysis, the attendance rate of 65.2% in the successfully contacted individuals within the intervention group (n ؍ 204) was increased by 47.8% over that in the control group. In the univariate analysis, attendance for selfpaying patients (25.4%) was worse than that for any group. In the logistic regression analysis, both the reminder telephone call intervention and the payment source were independent predictors of attendance. In the group that was called successfully (n ؍ 204), there was no association between attendance and the recipient of the telephone call.Conclusions. Telephone reminders are a very effective method of increasing attendance in a hospital-based adolescent clinic. The reminder is a consistently effective intervention whether the message is delivered to the patient, to the parent or other family member, or to a telephone answering machine. Adolescent patients whose visits are not covered by Medicaid or commercial insurance are least likely to attend their clinic appointments, and a telephone call reminder has no effect on this pattern. Pediatrics 1998;101(6). URL: http://www. pediatrics.org/cgi/content/full/101/6/e6; adolescents, appointment compliance, telephone reminder.ABBREVIATIONS. CI, confidence interval; OR, odds ratio; RR, rate ratio; SES, socioeconomic status.A major limitation in health care delivery to adolescents is their poor attendance at ambulatory clinics. The failed appointment rate in this age group can be as high as 60%.1-6 A recent large national surve...