Importance of home study visit capacity in dementia studies

The importance of home research study visit capacity in Alzheimer's disease (AD) studies is unknown.

All evaluations are from the prospective Adult Changes in Thought study. Based on analyses of factors associated with volunteering for a new in-clinic initiative, we analyzed AD risk factors and the relevance of neuropathologic findings for dementia comparing all data including home visits, and in-clinic data only. We performed bootstrapping to determine whether differences were greater than expected by chance.

Of the 1781 people enrolled during 1994-1996 with ≥1 follow-up, 1369 (77%) had in-clinic data, covering 61% of follow-up time. In-clinic data resulted in excluding 76% of incident dementia and AD cases. AD risk factors and the relevance of neuropathologic findings for dementia were both different with in-clinic data.

Limiting data collection in AD studies to research clinics alone likely reduces power and also can lead to erroneous inferences.