COVID-19 pandemic's relationship with enrollment at US Alzheimer's Disease Research Centers.

Introduction: We aimed to characterize the COVID-19 pandemic's relationship with enrollment in US Alzheimer's Disease Research Centers (ADRCs).

Methods: Using data on 10,105 participants from 30 ADRCs, we conducted interrupted time series analyses to assess the relationship of the pandemic with enrollment and calculate projected dates of enrollment recovery.

Results: Participants enrolled during the pandemic (vs pre-pandemic) were more likely to have dementia and be referred by health professionals. The pandemic was associated with a 77% drop in enrollment, with projected trend recovery in March 2024 and 100% recovery in September 2024. COVID was associated with a 91% drop in Black/African American participants, compared to 71% in White participants. Enrollment of both Hispanic and female participants was declining 1.4% and 0.3%/month pre-pandemic.

Discussion: Funders and researchers should account for ongoing COVID-19 impact on ADRD research enrollment. Strategies to speed enrollment recovery are needed, especially for Black/African American and Hispanic groups.

Highlights: Tested COVID pandemic association with enrollment at Alzheimer's Disease Research Centers. During versus pre-pandemic enrollees differed on demographic and clinical variables. Interrupted time series analyses: immediate 77% drop in enrollment related to COVID. Recovery projections: trend recovery in March 2024, 100% recovery in September 2024. Enrollment of African American and Hispanic participants should be prioritized.