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United States Department of Agriculture

Agricultural Research Service

Research Project: Dietary Guidelines Adherence and Healthy Body Weight Maintenance Title: Factors influencing enrollment of African Americans in the look AHEAD trial

Authors
item Mount, David -
item Davis, Craylen -
item Kennedy, Betty -
item RAATZ, SUSAN
item Dotson, Kathy -
item Gary-Webb, Tiffany -
item Thomas, Sheikilya -
item Johnson, Karen -
item Espeland, Mark -

Submitted to: Clinical Trials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 5, 2011
Publication Date: November 7, 2011
Citation: Mount, D.L., Davis, C., Kennedy, B., Raatz, S.K., Dotson, K., Gary-Webb, T.L., Thomas, S., Johnson, K., Espeland, M.A. 2011. Factors influencing enrollment of African Americans in the look AHEAD trial. Clinical Trials. 9:80-89.

Interpretive Summary: Many factors influence recruitment of African Americans into clinical trials; however, the influence of eligibility criteria may not be widely appreciated. We evaluated the Look AHEAD (Action for Health in Diabetes) trial screening process to determine the effect eligibility criteria had on the enrollment of African Americans. Look AHEAD is a large clinical trial to examine whether intensive lifestyle intervention reduces the long-term risk of major cardiovascular events in adults with type 2 diabetes. Look AHEAD screened 28,735 individuals for enrollment, including 6,226 (21.7%) who were self-identified African Americans. Of these volunteers, 12.9% of the African Americans compared to 19.3% of all other screenees ultimately enrolled (p<0.001). Higher levels of blood pressure, heart rate, HbA1c, and serum creatinine among African American screenees accounted for the greater proportions excluded (all p<0.001) for participation. African Americans were more often ineligible for the Look AHEAD Trial due to comorbid conditions.

Technical Abstract: BACKGROUND: Many factors have been identified that influence the recruitment of African Americans into clinical trials; however, the influence of eligibility criteria may not be widely appreciated. We used the experience from the Look AHEAD (Action for Health in Diabetes) trial screening process to examine the differential impact eligibility criteria had on the enrollment of African Americans compared to other volunteers. METHODS: Look AHEAD is a large randomized clinical trial to examine whether assignment to an intensive lifestyle intervention designed to produce and maintain weight loss reduces the long-term risk of major cardiovascular events in adults with type 2 diabetes. Differences in the screening, eligibility, and enrollment rates between African Americans and members of other racial/ethnic groups were examined to identify possible reasons. RESULTS: Look AHEAD screened 28,735 individuals for enrollment, including 6,226 (21.7%) who were self-identified African Americans. Of these volunteers, 12.9% of the African Americans compared to 19.3% of all other screenees ultimately enrolled (p<0.001). African Americans no more often than others were lost to follow-up or refused to attend clinic visits to establish eligibility. Furthermore, the enrollment rates of individuals with histories of cardiovascular disease and diabetes therapy did not markedly differ between the ethnic groups. Higher prevalence of adverse levels of blood pressure, heart rate, HbA1c, and serum creatinine among African American screenees accounted for the greater proportions excluded (all p<0.001). CONCLUSIONS: Compared to non-African Americans, African American were more often ineligible for the Look AHEAD Trial due to comorbid conditions. Monitoring trial eligibility criteria for differential impact, and modifying them when appropriate, may ensure greater enrollment yields.

Last Modified: 8/19/2014
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