Clinical trials that assessed Activities of Daily Living (ADL) or Instrumental Activities of Daily Living (IADL) in a population of community-dwelling frail elderly who received an intervention aimed at preventing disability were eligible for inclusion in the review. Eligible participants had to fulfil at least one of the specified criteria described by Ferrucci 2004 for the definition of frail elderly. Studies that equalised frailty solely on the presence of disabilities, chronic illness, eligibility of care or discharge from hospital were excluded.
Included interventions varied. Most were physical exercise interventions; 20% of the studies included nutritional interventions. Most physical exercise interventions (75%) were multi-component and included one or more aspects of the following: physical exercise training; endurance training; resistance training; and nutritional advice/provision. Most studies included a no intervention and/or encouragement control group; some included a lower level or less intense intervention as well or instead of a no intervention control. Mean age of included participants ranged from 76 to 83 years. In addition to assessing ADL/IADL, included studies commonly assessed outcomes such as functional capacity, physical activity, physical fitness, mobility and weight gain. Adverse events were assessed in a little over 50% of the studies. Follow-up and intervention duration ranged from 10 weeks to 18 months, but most studies carried out assessments at multiple time points with a final time point of less than one year.
Two reviewers independently assessed studies for inclusion; disagreements were resolved through consensus or the involvement of a third reviewer if required.