Strategies to Improve Immunization Rates and Well-child Care in a Disadvantaged Population: a Cluster Randomized Controlled Trial

Objective: To measure the effect of a multimodal intervention on well-child care visit (WCV) and immunization rates in an inner-city population.

Design: Cluster randomized controlled trial.

Setting And Participants: One-year cohort of 2843 infants born at a hospital in an integrated inner-city health care system.

Interventions: Eleven clinics were randomly allocated to 1 of 3 study arms: WCV intervention (n = 3), immunization intervention (n = 4), and controls (n = 4). Interventions to improve immunization and WCV rates included both patient-based and clinic-based activities.

Main Outcome Measures: Up-to-date status with childhood immunizations and WCVs by age 12 months (primary) and health care utilization and charges (secondary).

Results: Compared with the control arm, the WCV and immunization arms had 5% to 6% higher immunization rates and 7% to 8% higher WCV rates. In multivariate analyses that accounted for the clustered nature of the data, the number of immunizations received was greater in the WCV arm than in controls. However, neither the WCV nor the immunization intervention increased WCV or immunization up-to-date rates. The WCV arm had slightly higher health care charges. Neither intervention affected emergency, urgent care or inpatient utilization.

Conclusions: This multimodal intervention produced a small increase in the number of childhood immunizations delivered. However, patient- and clinic-based methods did not lead to significant increases in WCV or immunization up-to-date rates after controlling for other factors. Methods found in some settings to increase immunization up-to-date rates may not be as effective in a population of inner-city socioeconomically disadvantaged children.