Effective multicomponent-interventions on physical capacity, cognitive function and instrumental-activities-of-daily-living are not the same for elderly people with normal and mild-impaired-cognition

Background: Ageing is associated with high risk for physical and cognitive impairments, which may lead to disability and possible loss of independence. From individual, societal and economic perspectives it is of high importance to find strategies that prevent disability and maintain independence in older people. Evidence suggests that both, physical exercises and cognitive training are effective in increasing physical capacity and cognitive function. Moreover, multicomponent interventions (MCT) that combine physical exercises and cognitive training seem to be most effective in improving cognition in older people. However, literature is inconclusive if MCTs are superior to active comparison interventions, if delivery modes matter, and if people can transfer achieved effects to instrumental activities of daily living (IADL). Purpose: This systematic review incorporating a network Meta-analysis aimed to 1) identify MCTs that were effective on physical capacity and/or cognitive function and achieved a transfer of these effects into IADL in community-dwelling elderly people with normal cognition (NC) and mild impaired cognition (MCI); 2) provide a rating on the best interventions per outcome and 3) to evaluate MCTs' mode of delivery. Methods: A comprehensive systematic electronic database search was performed. Eligible studies were randomized controlled trials investigating the effectiveness of MCT on IADL and/or physical capacity (e.g. muscle strength) and/or cognitive function (overall cognition and/or domains) in comparison to active control interventions and/or no intervention in community dwelling older people (age ? 55years) with NC, subjective cognitive decline or MCI in accordance to Petersen criteria. Data synthesis incorporated a Bayesian network meta-analysis to compare direct and indirect treatment effects. Results: Six studies in participants with MCI (n=1088) and eleven studies in participants with NC (n=670) were included. Twelve effective MCTs were detected, whereof five MCTs were superior to physical exercises or cognitive training alone in improving physical capacity and/or cognitive function, however none of these MCTs improved IADL. Effective MCTs represented a wide range of interventions with respect to content and dose. The most consistent effectiveness of MCTs was identified in people with MCI for a combined intervention of balance exercises plus cognitive training and in people with NC for an exergame intervention. Moreover, effective MCTs differed in their delivery mode for people with NC and MCI. In people with MCI sequential delivery of MCTs were more effective, whereas in people with NC sequential and simultaneous delivery of MCTs were effective. Conclusion(s): The results from this network Meta-analysis confirmed the notion that MCTs are more effective compared to active or no treatment in community dwelling elderly people with and without MCI. Moreover, the results suggest that the most effective MCT interventions for people with NC are not the most effective for people with MCI. Implications: The results stress the importance to develop specifically tailored multi-component interventions for people with MCI. Furthermore, the results highlight the need to develop a theoretical model of the mediating effects of physical capacity and cognitive function on IADL in people with MCI to design multi-component interventions that have the potential to effectively improve IADL