Using Bayesian hierarchical models for controlled post hoc subgroup analysis of clinical trials: application to smoking cessation treatment in American Indians and Alaska Natives.

Clinical trials powered to detect subgroup effects provide the most reliable data on heterogeneity of treatment effect among different subpopulations. However, pre-specified subgroup analysis is not always practical and post hoc analysis results should be examined cautiously. Bayesian hierarchical modelling provides grounds for defining a controlled post hoc analysis plan that is developed after seeing outcome data for the population but before unblinding the outcome by subgroup. Using simulation based on the results from a tobacco cessation clinical trial conducted among the general population, we defined an analysis plan to assess treatment effect among American Indians and Alaska Natives (AI/AN) enrolled in the study. Patients were randomized into two arms using Bayesian adaptive design. For the opt-in arm, clinicians offered a cessation treatment plan after verifying that a patient was ready to quit. For the opt-out arm, clinicians provided all participants with free cessation medications and referred them to a Quitline. The study was powered to test a hypothesis of significantly higher quit rates for the opt-out arm at one-month post randomization. Overall, one-month abstinence rates were 15.9% and 21.5% (opt-in and opt-out arm, respectively). For AI/AN, one-month abstinence rates were 10.2% and 22.0% (opt-in and opt-out arm, respectively). The posterior probability that the abstinence rate in the treatment arm is higher is 0.96, indicating that AI/AN demonstrate response to treatment at almost the same probability as the whole population.

Using focus groups in community-based participatory research: challenges and resolutions.

A community-based participatory approach requires that community members be involved in all phases of the research process. We describe three focus group studies with American Indians in Kansas and Missouri, using a newly developed method of conducting and analyzing focus groups with community input (72 focus groups, 519 participants). We conducted two needs assessment studies focused on barriers to breast and colorectal cancer screening and one study focused on Internet use for gathering health information. Community members and researchers collaborated to develop guides for the focus group moderators. Community organizations and our community advisory board conducted recruitment, and we trained and employed community members as moderators, assistant moderators, and analysts. Our community partners also helped with dissemination of research findings to their constituents. The methodologic approach and data from these three studies will allow us to more appropriately address health disparities in the American Indian community, with full community support for our research.

Assessing the scientific accuracy, readability, and cultural appropriateness of a culturally targeted smoking cessation program for American Indians.

This study assesses educational materials developed for the All Nations Breath of Life smoking cessation program (targeted for American Indians and Alaska Natives) for scientific accuracy, readability and other literacy factors, and cultural appropriateness. The authors used a scientific review panel of experts in smoking cessation representing epidemiology, medicine, and psychology; the suitability assessment of materials (SAM) and the simplified measure of gobbledygook (SMOG) reading grade level formulas; and review by Native program facilitators and pilot participants. Materials were scientifically accurate and culturally appropriate. The mean SAM score was 80% (superior rating), and the average reading grade level was 7.1 using the Fry formula (part of the SAM) and 8.4 using the SMOG formula (difference was not statistically significant). Based on this project, the SAM can be used in combination with scientific review and input from community members during formative research to assess and modify educational materials for a targeted population.