Objectives: To assess the effectiveness and cost of interactive voice response (IVR) reminders for influenza vaccination compared with postcards, among adults with asthma or chronic obstructive pulmonary disease (COPD).
Study design: Pragmatic, 3-arm, randomized control trial.
Methods: The trial was conducted in an integrated healthcare organization during 2012 and 2013, using an existing IVR system. All adults aged 19 through 64 years with asthma or COPD (n = 12,285) were randomized to receive 1 of the following vaccination reminders: 1) postcard reminder only, 2) IVR reminder only, or 3) postcard plus IVR reminder. The primary outcome was influenza vaccination by October 31, 2012; the secondary outcomes were influenza vaccination by December 31, 2012, and by March 31, 2013.
Results: For subjects receiving an IVR call, 57% received a message on their answering machine; 27% answered the call; and 16% were not reached. Influenza vaccination rates were 29.5%, 31.1%, and 30.6% in the postcard-only, IVR-only, and postcard-plus-IVR study arms, respectively. After controlling for relevant covariates, IVR reminders were not significantly more or less effective than postcard reminders. Program costs were $0.78, $1.23, and $1.93 per subject for postcard-only, IVR-only, and postcard-plus-IVR reminders, respectively. Extrapolating costs to the entire population at the study site that typically receives influenza vaccination reminders (approximately 100,000 individuals), reminder costs would have been $0.55, $0.05, and $0.60 per subject for postcard-only, IVR-only, and postcard-plus-IVR reminders, respectively.
Conclusions: IVR reminders are not more effective at promoting influenza vaccination than postcard reminders, but IVR reminders may be less expensive for large patient populations.