Formal and Informal Care Utilization in Mild Cognitive Impairment and Mild Dementia due to Alzheimer's Disease: Cross-Sectional and Longitudinal Analyses of RUD-Lite Data from the Tauriel Study.

INTRODUCTION: Evaluating formal and informal care utilization in Alzheimer's disease (AD) is crucial for assessing the economic impact of novel disease-modifying treatments. The Resource Utilization in Dementia-Lite (RUD-Lite) scale is widely used to measure care utilization in dementia; however, RUD-Lite data are limited for mild cognitive impairment (MCI) and mostly from observational studies. We analyzed RUD-Lite data from a study of semorinemab (NCT03289143) in MCI (i.e., prodromal AD) and mild AD dementia (i.e., mild AD) to explore potential differences in care utilization between observational and interventional studies. METHODS: We analyzed cross-sectional and longitudinal RUD-Lite indices in prodromal (pAD: n = 160) and mild (mAD: n = 288) AD groups, examining formal care usage and informal caregiver time. Unadjusted and adjusted analyses were performed on longitudinal data. North American and European cohorts were compared to explore potential regional differences. RESULTS: More informal caregiving assistance was required for mAD versus pAD participants at baseline and the mAD group demonstrated significant greater increases over 18 months. Cross-sectional data indicated more caregiver assistance for instrumental activities of daily living in North America versus Europe, with comparable longitudinal increases in caregiver assistance across regions. CONCLUSION: Longitudinal RUD-Lite changes in interventional early AD studies are detectable but smaller than in observational studies, possibly due to differences in cohort characteristics. These factors, along with subtle regional differences in care utilization, should be considered when using observational data to guide interventional trials.