Effect of telephone reminder/recall on adolescent immunization and preventive visits - Results from a randomized clinical trial

Objective: To measure the effect of telephone-based reminder/ recall on immunization and well-child care(WCC) visit rates among adolescents in urban practices. Design: Randomized clinical trial of telephone-based reminder/ recall over 18 months. Setting: Four urban primary care practices. Participants: Adolescents aged 11 to 14 years. Intervention: Adolescents within practices were randomized to study (n=1496) or control groups (n=1510). The study group was sent audiotaped telephone reminders about a scheduled or needed immunization or WCC visit. Households were called weekly if there was no response; telephone numbers were updated weekly. Controls received standard care. Results: Baseline demographics and immunization and WCC visit rates were similar for study and control groups. The intervention was largely ineffective in improving immunization or WCC visit rates. Although at the end of the study, the study group had slightly higher hepatitis B coverage (3 vaccinations)(62% vs 57.8%; P=.02), WCC visits were the same (53% and 54%), and impact on other vaccinations was minimal. The effect of reminder/recall was equivalent across demographic subgroups (eg, age, race/ethnicity, insurance). The major factor limiting intervention effectiveness was inaccurate telephone numbers. Seventy-one percent of study subjects with single telephone numbers throughout the study had a WCC visit vs 25% of study subjects with multiple/changed telephone numbers and 54% of controls (P <.001). Conclusions: An intensive telephone reminder and recall system was only minimally successful in improving immunization and WCC visit rates among urban adolescents. Lack of success was largely owing to changed or inaccurate telephone numbers.