Impacts of subjective cognitive decline and mild cognitive impairment on the effectiveness of an exercise intervention among community-dwelling (Pre)frail older adults

Background: Subjective cognitive decline (SCD) is prevalent in community-dwelling (pre)frail older adults. This study aimed to investigate whether baseline subjective cognitive decline (SCD) and mild cognitive impairment (MCI) impacted the effectiveness of an exercise intervention among (pre)frail older adults. Methods: This is a post hoc analysis of a stepped-wedge cluster randomized trial among (pre)frail older adults across six communities. The intervention effectiveness was examined among (pre)frail older people among subgroups with normal cognition (n = 44), SCD (n = 58), or MCI (n = 30). Results: The normal cognition group had both immediate and persistent treatment responses to most outcomes. The SCD group showed positive responses to frailty (0-, 12-, 24 week), ambulation and dynamic balance (0week), and depressive symptoms (12-week). The MCI group exhibited immediate improvement in frailty, cognition, depressive symptoms, social support and QoL, which persisted only in frailty status, social support and mental QoL at follow-ups. The MCI group showed superior immediate responses to cognitive function and depressive symptoms compared to another two subgroups. No differences were found between the normal cognition and SCD groups except for cognitive status (12-week). Conclusions: (Pre)frail people with SCD or MCI had fewer improved outcomes compared to those with normal cognition regardless of immediate or persistent improvements. The incorporation of cognitive strategies with exercise interventions are recommended among (pre)frail older adults with SCD or MCI.