Cost and utilization avoidance with mail prompts: a randomized controlled trial.

OBJECTIVE To study the medical service utilization changes and return on investment from a health plan's direct mailings that either encouraged members to receive influenza vaccinations or encouraged members to call a nurse advice service. STUDY DESIGN Randomized controlled trial with 2 intervention groups and 1 control group consisting of all members over age 65 years who were enrolled in 5 states in the Blue Cross and Blue Shield Government-wide Service Benefit Plan. Sample size was 134,791 individuals. METHODS Administrative claims-based influenza, pneumonia, heart failure, and respiratory inpatient bed days, emergency department (ED) visits, physician evaluation and management visits, other outpatient visits, and nurse advice call rates were compared between the intervention and control groups. RESULTS The influenza mailing intervention group experienced 2.87% (P = .033) fewer conditionrelated inpatient bed days and 7.25% (P = .101) fewer condition-related ED visits. The nurse advice service mailing intervention group experienced 7.65% (P <.001) fewer condition-related inpatient bed days and 6.75% (P = .125) fewer condition-related ED visits. Per dollar spent, the return on investment was estimated to be $2.51 for the influenza mailing intervention and $24.24 for the nurse advice mailing intervention. CONCLUSIONS Administrative claims data suggest that members respond to health plan mailings. By mailing information to their members, health plans can affect rates of medical service utilization and generate cost savings.