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

BACKGROUND: 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. 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\u27s Ask about Aspirin Initiative. METHODS: Twenty-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. RESULTS: The analysis demonstrated that demographic characteristics did not differ significantly between the intervention and control territories created by the territory design software. CONCLUSIONS: The 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 REGISTRATION: National Institutes of Health (Clinical Trials.gov), Identifier: NCT02607917 . Registered on 16 November 2015

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

Abstract Background 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. 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. Methods Twenty-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. Results The analysis demonstrated that demographic characteristics did not differ significantly between the intervention and control territories created by the territory design software. Conclusions The 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 registration National Institutes of Health (Clinical Trials.gov), Identifier: NCT02607917. Registered on 16 November 2015

Factors associated with use of percutaneous coronary intervention among elderly patients presenting with ST segment elevation acute myocardial infarction (STEMI): Results from the ISACS-TC registry

Background A substantial proportion of elderly with ST segment elevation myocardial infarction (STEMI) do not undergo percutaneous coronary intervention (PCI). We sought to investigate factors associated with the decision not to perform coronary angiography at admission in these patients. Methods We evaluated 1315 STEMI patients aged 65\ua075\ua0years old enrolled in the International Survey of Acute Coronary Syndromes in Transitional Countries (ISACS TC) registry between October 2010 and February 2015. They were compared with 6667 patients aged <\ua075\ua0years old enrolled in the registry in the same time frame. Results Elderly patients were less likely to undertake invasive coronary evaluation compared with younger patients (62.1% vs. 78.9; p\ua0<\ua00.001%). In the older group there were a lower proportion of patients presenting <\ua012\ua0h after symptom onset (66.5% vs.76.9%, p\ua0<\ua00.001), and a higher prevalence of comorbidities. Few elderly were treated with current recommended evidence based treatments (aspirin, clopidogrel, heparins, beta-blocker, statins, and ACE-inhibitors). Logistic analysis adjusted for age and sex showed that older age was associated with underuse of coronary angiography (OR 0.46, 95% CI: 0.41\u20130.53, p\ua0<\ua00.001). Clinical factors that were associated with underuse of angiography in patients over 75 were: female sex (OR: 0.77), presence of comorbidities (OR: 0.91), anemia (OR: 0.44) and late hospital admission (OR: 0.89). Conclusions In the ISACS-TC, more than one third of the elderly with STEMI did not undergo coronary angiography at admission. Sex, comorbidities, and late hospital admission were independent factors associated with the underuse of PCI in these patients