Everyday functioning in a community‐based volunteer population: Factors associated with concordance between participant and study partner—Report

Abstract

AbstractBackgroundWith the shift towards preclinical phases of Alzheimer’s disease (AD) and other neurodegenerative diseases in research studies and clinical trials, the question arises if participants can reliably self‐report their level of everyday functioning. Here, we aim to investigate the factors related to concordance between participant‐ and study partner‐report versions of the Amsterdam Instrumental Activities of Daily Living Questionnaire (A‐IADL‐Q) in a community‐based volunteer population.MethodCommunity based volunteers (participants) and their study partners were recruited from a Dutch brain research registry. IADL concordance between participant and study partner was investigated using intraclass correlation coefficient (ICC). Dyads were subsequently categorized as (1) concordant (<2 points differences in A‐IADL‐Q score); (2) discordant, with study partner reporting more difficulties (study partner>participant) and (3) discordant, participant>study partner. Multinomial logistic regression models were used to investigate the association between subjective cognitive decline, depressive symptoms (Geriatric Depression Scale‐5), type of relationship, objective cognitive functioning (Cognitive Online Self‐Test Amsterdam), and concordance as dependent variable.ResultA total of 1213 participants (18‐93 years of age, 68.3% female) and 1213 study partners (18‐88 years, 45.8% female) completed the A‐IADL‐Q. The majority of participants (52.8%) and study partners (59.5%) reported no IADL difficulties. Figure 1 shows the percentage of IADL difficulty reported for individual activities by both participants and study partners. Of the dyads, 653 (53.8%) were in concordance, with an ICC of .55 (95%CI=[.51, .59], Figure 2). Depressive symptoms and memory complaints increased the odds of participants reporting more IADL difficulties compared to their study partner (odds ratio (OR)=1.31, p<.01 and OR=2.56, p<.01, Table 1). An inverse association was found between A‐IADL‐Q and concordance, to the extent that higher A‐IADL‐Q scores were associated with a lower odds of study partner>participant discordance (OR=0.68, p<.01).ConclusionA slight majority of dyads showed concordance between participant‐ and study partner‐reported IADL scores. Our findings suggest that concordance is less likely in the presence of memory complaints, depressive symptoms and with lower levels of everyday functioning. These findings implicate that participant‐ and study partner report capture different aspects of functional decline, which might influence the study design of longitudinal aging studies.