Evaluating the impact of multilevel evidence-based implementation strategies to enhance provider recommendation on human papillomavirus vaccination rates among an empaneled primary care patient population: a study protocol for a stepped-wedge cluster randomized trial.

Background: Each year, human papillomavirus (HPV) causes 30,000 cancers in the USA despite the availability of effective and safe vaccines. Uptake of HPV vaccine has been low and lags behind other adolescent vaccines. This protocol describes a multilevel intervention to improve HPV vaccination rates.
Methods: Using a cluster randomized trial, we will evaluate the independent and combined impact of two evidence-based implementation strategies with innovative enhancements on HPV vaccination rates for female and male patients. The clusters are six primary care sites providing care to pediatric populations. We will use a stepped-wedge cluster randomized design, including process evaluation, to test the hypothesis that compared with the current course of care and a practice-level intervention using reminder-recall interventions coupled with provider-level audit and feedback with education increases HPV vaccination rates in exposed clusters. The factorial design allows us to use a single trial to test these two interventions and to assess each individually and in combination. Our design has four 12-month steps. The first step will be a baseline period; data collected during it will provide a within-practice control group for each cluster. Second, two clusters will be randomly assigned to receive intervention 1 (reminder and recall), and two clusters will be randomly selected to receive intervention 2 (audit and feedback with education). Third, the other two clusters will be randomly allocated to intervention 1 or 2. Clusters initially with intervention 1 will be randomly allocated to 1 + 2 or 1; clusters initially with intervention 2 will be randomly allocated to 1 + 2 or 2. Fourth, all clusters will receive both interventions. To ensure balance of patient numbers across interventions, we will use block randomization at the first step, with the six clusters grouped into three pairs according to volume. Our primary outcome will be vaccination rates.
Discussion: Results of our clinical trial and process evaluation will provide evidence showing whether practice- and provider-level interventions improve HPV vaccination rates and will offer insight into contextual factors associated with direction and magnitude of trial outcomes.
Trial Registration: ClinicalTrials.gov, NCT03501992 , registered April 18, 2018.