The ACAD study is a multi-site collaborative investigation aimed at exploring the genetic and environmental risk factors for AD among Asian Americans and Asian Canadians. With the rising prevalence of AD in these populations, ACAD aims to enhance our understanding of how these factors contribute to the disease's progression. Data collection was designed to minimize participant burden while considering the historical stigma of dementia in Asian cultures. Standardizing diagnostic procedures across sites ensures consistent, high-quality data.

We analyzed 42 participants who had previously undergone a consensus-based diagnostic process across seven ACAD recruiting sites. The cohort included a spectrum of cognitive abilities, from cognitively healthy to cognitively impaired. Cognitive assessments were conducted in six languages to accommodate linguistic diversity and preferences among participants. Two independent neurologists re-evaluated the consensus diagnoses. Cohen’s Kappa coefficient measured inter-rater reliability, providing a robust assessment of diagnostic consistency across evaluators and sites.

Our results showed an observed agreement rate of 88% between the consensus process at the recruiting sites and the two external raters. Cohen’s Kappa value was also calculated at 0.835, indicating a near-perfect agreement. This high level of consistency affirms the reliability of the ACAD study’s diagnostic protocol, demonstrating that standardized procedures across sites, even with language variability, yield consistent diagnostic outcomes.

The high inter-rater agreement underscores the effectiveness of the ACAD consensus process in delivering reliable diagnoses. These findings emphasize the importance of maintaining standardized diagnostic protocols across multiple research sites. This study's success not only paves a way for large-scale research into Alzheimer's disease in underrepresented groups but also significantly advances global efforts to foster inclusivity in AD research.