Study partner factors on cognitive function index scores among participants screened for the A4 study

Abstract

AbstractBackgroundThe Cognitive Function Index (CFI) is an evaluation of participants’ cognitive and functional decline. Alzheimer’s disease (AD) clinical trials, including Preclinical trials, require participants to have a study partner (SP) to help evaluate participant cognitive and functional performance. Past studies in early AD dementia and Mild Cognitive Impairment populations have shown that spousal SPs are more accurate at providing cognitive information than non‐spousal SPs. We aimed to investigate if SP variables are associated with participant and SP reported CFI score among cognitively normal participants screened for the A4 Study.Method6155 Participants and 5953 Study Partners completed the screening CFI in the A4 Study. The CFI is a 14‐item questionnaire completed by both the SP and the participant with higher scores meaning increased decline over the past year. SPs were categorized as: Spouse, Adult Child, Friend/Companion, and Other. SPs were also categorized based on the number of weekly hours spent with the participant in‐person (more vs less than 68 hours per week). Associations with participant and SP reported screening CFI were assessed using a multiple regression model adjusting for participant age, gender and education, but without adjustments for multiple comparisons.ResultsSPs were female for 40% of female participants and 90% of male participants. Spousal SPs report spending 103 +/‐ 42 hours per week with the participants, while the other groups reported much fewer hours (Adult child: 17 +/‐30, Friend/Companion: 21 +/‐ 35, Other: 27 +/‐ 40). There was no association between SP group and participant CFI score. There was an observed association between SP group and SP CFI score (F=6.54, p < 0.001). Friends/Companions (beta=‐0.30+/‐0.19, p<0.001) and Other (beta=‐0.19 +/‐0.11, p=0.07) groups reported lower scores on the CFI than Spouses. There were no differences by SP gender or number of hours spent in person per week.ConclusionThis cross‐sectional analyses showed preliminary evidence that SP type can influence the SP score on the screening CFI although there is no evidence of SP influence on participant reported CFI. Longitudinal data, when available at trial end, will help assess these associations over time and if study partner type can predict future cognitive decline.