Use of a Geographic Information System to create treatment groups for group-randomized community trials: The Minnesota Heart Health Program

Brittany Krzyzanowski,Len Kne,Milton Mickey Eder,Kevin Peterson,Alan T Hirsch,Steven M Manson,Sue Duval,Russell V Luepker,Niki Oldenburg

doi:10.1186/s13063-019-3284-9

Abstract

BackgroundGroup-randomized trials of communities often rely on the convenience of pre-existing administrative divisions, such as school district boundaries or census entities, to divide the study area into intervention and control sites. However, these boundaries may include substantial heterogeneity between regions, introducing unmeasured confounding variables. This challenge can be addressed by the creation of exchangeable intervention and control territories that are equally weighted by pertinent socio-demographic characteristics. The present study used territory design software as a novel approach to partitioning study areas for The Minnesota Heart Health Program’s “Ask about Aspirin” Initiative.MethodsTwenty-four territories were created to be similar in terms of age, sex, and educational attainment, as factors known to modify aspirin use. To promote ease of intervention administration, the shape and spread of the territories were controlled. Means of the variables used in balancing the territories were assessed as well as other factors that were not used in the balancing process.ResultsThe analysis demonstrated that demographic characteristics did not differ significantly between the intervention and control territories created by the territory design software.ConclusionsThe creation of exchangeable territories diminishes geographically based impact on outcomes following community interventions in group-randomized trials. The method used to identify comparable geographical units may be applied to a wide range of population-based health intervention trials.Trial registrationNational Institutes of Health (Clinical Trials.gov), Identifier: NCT02607917. Registered on 16 November 2015.

Highlights

Group-randomized trials of communities often rely on the convenience of pre-existing administrative divisions, such as school district boundaries or census entities, to divide the study area into intervention and control sites
Multisite community intervention trial (CIT) often rely on the convenience of pre-existing administrative divisions to delineate the geographical regions that will be randomized to the intervention and control groups, and these units are not guaranteed to be exchangeable in terms of community characteristics
The present study evaluated the utility of a regionalization tool as a novel approach to create balanced territories for public health and community intervention research (Business Analyst Territorial Design, ESRI, Redlands, CA, USA)

Summary

Introduction

Group-randomized trials of communities often rely on the convenience of pre-existing administrative divisions, such as school district boundaries or census entities, to divide the study area into intervention and control sites These boundaries may include substantial heterogeneity between regions, introducing unmeasured confounding variables. ESRI’s Business Analyst Extension is one of many existing tools developed for a traditional use in optimizing business and marketing strategies, using consumer demographic datasets that would be applicable to corporate efforts to create regions or zones to “balance” sales, service, and advertising efforts We hypothesized that such an analytic approach would be useful to create optimal territories for dissemination of population-based community health interventions. To the best of our knowledge, this study represents the first use of this territory design tool by a public health intervention study to balance geographic units at baseline

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Results

Conclusion