Five-Year Cognitive Trajectories in Individuals with Mild Cognitive Impairment and Mild Dementia: Associations with Attendance in a Multimodal Day-Care Program

Introduction: Mild cognitive impairment (MCI) and mild dementia are critical stages at which non-pharmacological strategies may help delay further cognitive decline. While multimodal interventions show short-term benefits, evidence on long-term cognitive trajectories, particularly regarding adherence, remains limited. We examined five-year changes in cognitive function among individuals with MCI or mild dementia participating in a multimodal daycare program, focusing on adherence levels. Methods: This single-arm longitudinal observational study was conducted at the University of Tsukuba Hospital (April 2013–February 2020). The multimodal program (exercise, cognitive training, music and art therapy) run 3 days/week in two 2-hour sessions (morning and afternoon). Most participants (approximately 94%) attended once weekly; some attended more often. Cognitive function was assessed annually using the Japanese version of the Mini-Mental State Examination (MMSE-J). Participants were grouped according to attendance thresholds (i.e., the proportion of sessions attended out of the total sessions scheduled: 50%, 60%, 70%, and 80%) to examine the association with cognitive outcomes. Mixed-effects models adjusted by propensity scores evaluated longitudinal MMSE-J changes. Results: Among 96 participants (mean age: 71.4; baseline MMSE-J: 26.2; mean participation: 3.8 years), the average annual MMSE-J decline was 0.53 points (95% CI: -0.70, -0.36). At the 60% threshold, ≥60% attendance was associated with a 2.3-point decline (vs. 6.6 points for <60%), yielding a -4.6-point difference (95% CI: -7.38, -1.73). Similar findings appeared at 70% (-4.2 points; 95% CI: -6.78, -1.55) over five years. No significant interactions were observed at the 50% or 80% threshold. Conclusion: Consistent participation—attending at least 60% of sessions—in a multimodal daycare program was associated with relatively stable cognitive trajectories over five years, indicating the importance of sustained engagement. The findings support the potential value of continued participation and warrant further investigation in controlled settings.