INFLUENZA IMMUNIZATION IN A MANAGED CARE ORGANIZATION

OBJECTIVE:To compare the effects of different types of computer-genera ted, mailed reminders on the rate of influenza immunization and to ana lyze the relative cost-effectiveness of the reminders. DESIGN: Randomi zed controlled trial. SETTING: Multispeciality group practice. PATIENT S: We studied 24,743 high-risk adult patients aligned with a primary c are physician. INTERVENTION: Patients were randomized to one of four i nterventions: (1) no reminder, which served as control; (2) a generic postcard: (3) a personalized postcard from their physician: and (4) a personalized letter from their physician, tailored to their health ris k. MEASUREMENTS: The immunization rate was measured using billing data . A telephone survey was conducted in a subgroup of patients to measur e reactions to the mailed reminders. To evaluate the cost-effectivenes s, a model was constructed that integrated the observed effect of the interventions with published data on the effect of immunization on fut ure inpatient health care costs. MAIN RESULTS: All three of the remind ers studied increased the influenza vaccination rate when compared wit h the control group. The vaccination rate was 40.6% in the control gro up, 43.5% in the generic postcard group, 44.7% in the personalized pos tcard group, and 45.2% in the tailored letter group. The rates of immu nization increased as the intensity of the intervention increased (p < .0001). Seventy-eight percent of patients in the letter group deemed the intervention useful, and 86% reported that they would like to get reminders in the future. The cost-effectiveness analysis estimated tha t in a nonepidemic year, the net savings per 100 reminders sent would be $659 for the personalized postcard intervention and $735 for the ta ilored letter intervention. When these net cost-savings rates were eac h applied to the entire high-risk cohort of 24,743 patients, the estim ated total net savings was $162,940 for the postcard and $181,858 for the tailored letter. CONCLUSIONS: Although the absolute increase in im munization rates with the use of reminders appeared small, the increas es translated into substantial cost savings when applied to a large hi gh-risk population. Personalized reminders were somewhat more effectiv e in increasing immunization, and personalized letters tailored to the patients' condition were deemed useful and important by the individua ls who received them and had a beneficial indirect effect on patient s atisfaction.