Background: Patient reminders are often recommended to improve immunization rates. Many studies have evaluated reminders, and findings vary considerably. Systematic reviews are needed to help determine the effectiveness of patient reminders.

Objective: To examine the evidence supporting the effectiveness of patient reminder and/or recall (R/R) systems (letter or telephone contacts) as a strategy to improve immunization rates.

Design/Methods: Systematic review of published research, per methods of the Cochrane Collaboration. Studies were reviewed that used patient reminders (before visits or immunizations) or recall (patients who were behind). Articles with original data and immunization rates as outcomes (for children or adults) were examined if study designs involved randomized controlled trials (RCTs), controlled before-and-after studies (CBAs), or interrupted-time-series. Studies were reviewed independently by 2 readers. Reviewers utilized a standardized instrument to examine study design, quality(e.g., sources of bias), and outcomes (immunization rates).

Results: The search strategy identified 147 studies; 71 were fully reviewed and 29 studies met established validity criteria. 12 studies involved children and 17 studies involved adults. The table shows the number of studies in each category, study design (RCT or CBA), and the effect of R/R on immunization rates (+ effect, no effect, or R/R was combined with other interventions so the independent effects of R/R could not be assessed). 9/12 child studies had a positive effect of R/R (7-34 percentage points improvement in immunization rates, p<.05); 2/12 had no effect. 9/17 adult studies had a positive effect of R/R (6-31 percentage points improvement in immunization rates, p<.05); 2/17 had no effect. The effects of mail vs telephone R/R were similar.

Table 1 No caption available.
Full size table

Conclusions:Patient R/R systems improve immunization rates in child and adult populations. The optimal format of R/R systems needs to be determined.