Characteristics of the included studies
| Study; country | No. of participants (F/M, %) | Age, mean ± SD, yr | Assessment tool or measure* | Frailty level, no. of participants† | Design; duration‡ | Intervention category; intensity; frequency; duration | Control | Delivery of intervention | Outcome(s) |
|---|---|---|---|---|---|---|---|---|---|
| Binder et al.,54–56 2005, US | 119 (52/48§) | O: 83 ± 4 I: 83 ± 4 C: 83 ± 4 | Physical Performance Test¶ | I: mild to moderate frailty 66 C: mild to moderate frailty 49 | RCT; 9 mo | Mixed; moderate intensity; 3×/wk; 30 min (aerobic component) | Home exercises (primarily flexibility), monthly exercise classes | Exercise physiology technician | Frailty |
| Brown et al.,46 2000, US | 87 (57/43) | I: 83 ± 4 C: 83 ± 4 | Physical Performance Test | I: frail 48 C: frail 39 | RCT; 3 mo | Mobility/rehabilitation; light intensity; 3×/wk; duration NR | Home exercises (primarily flexibility), monthly exercise classes | NR | Frailty, mobility, physical function (including falls and quality of life) |
| Chandler et al.,48 1998, US | 100 (50/50) | O: 77.6 ± 7.6 I: 77.5 ± 7.1 C: 77.7 ± 7.8 | Inability to descend stairs step over step without holding railing | I: frail 50 C: frail 50 | CCT; 10 wk | Muscle-strengthening; resistance/strength training; 3×/wk; duration NR | Usual care | Physiotherapist | Frailty, physical function (including falls and quality of life) |
| Chen et al.,51 2010, Taiwan | 69 (53/47) | O: 75.40 ± 6.70 | Barthel Index (ADLs) | I: transitional frail 38 C: transitional frail 31 | RCT; 8 mo | Mobility/rehabilitation; light intensity; 3×/wk; 70 min | Usual care | Certified yoga instructor | Frailty |
| Chen et al.,28 2020, China | 70 (65/35§) | I: 76.97 ± 5.19 C: 75.27 ± 5.98 | Fried’s frailty phenotype | I: prefrail 33 C: prefrail 33 | RCT; 9 wk | Muscle-strengthening; resistance/strength training; 3×/wk; 45–60 min | Usual care | Physiotherapist or trained community centre worker | Frailty, mobility |
| Clegg et al.,31 2014, UK | 84 (71/29) | O: 79 ± 9.2 I: 79.4 ± 7.9 C: 78.0 ± 10.5 | Edmonton Frail Scale | Mean Edmonton Frail Scale score ± SD: I: 7.8 ± 2.4 C: 8.3 ± 2.7 | RCT; 12 wk | Muscle-strengthening; resistance/strength training; 5×/wk; < 15 min | Usual care | Physiotherapist | Frailty, mobility |
| Daniel,40 2012, US | 23 (61/39) | O: 77 ± 5.3 I: 78.13 ± 5.5, 80 ± 3.37 C: 72.6 ± 4.6 | Fried’s frailty phenotype | I: prefrail 8, 8 C: prefrail 7 | RCT; 15 wk | Mixed; intensity unknown; 3×/wk; 45 min | Usual care | Certified fitness professional | Frailty, mobility |
| de Jong et al.,45,57,58 2000, the Netherlands | 217 (70/30) | O: 78.7 ± 5.6 I: 76.7 ± 4.4 C: 79.3 ± 6.6 | Required health care service (e.g., home care or meal delivery) | I: frail 39 C: frail 37 | RCT; 17 wk | Mixed; moderate intensity; 2×/wk; 45 min | Social program | Teacher (researcher supervised) | Frailty, mobility, physical function (including falls and quality of life) |
| Faber et al.,42 2006, the Netherlands | 278 (79/21§) | I: 85.4 ± 5.9, 84.4 ± 6.4 C: 84.9 ± 5.9 | Fried’s frailty phenotype¶ | I: prefrail 25, 33; frail 36, 43; not frail 4, 4 C: prefrail 47; frail 36; not frail 7 | RCT; 20 wk | Muscle-strengthening; moderate intensity; 1×/wk for 4 wk, then 2×/wk for 16 wk; 90 min | Usual care | Instructor-led group sessions | Frailty, mobility, physical function (including falls and quality of life) |
| Gill et al.,44,59 2002, US | 188 (80/20) | O: 83 I: 82.8 ± 5.0 C: 83.5 ± 5.2 | Moderately frail if required > 10 s to perform rapid gait test or could not stand up from seated position in hardback chair with arms folded; severely frail if met both criteria | I: moderately frail 60, severely frail 34 C: moderately frail 56, severely frail 38 | RCT; 7 mo | Mobility/rehabilitation; intensity unknown; 3×/wk; duration NR | Individualized monthly health education sessions | Physiotherapist | Frailty, mobility, cognitive function, physical function (including falls and quality of life), use of health care services |
| Giné-Garriga et al.,41 2010, Spain | 51 (61/39§) | I: 83.9 ± 2.8 C: 84.1 ± 3.0 | > 10 s to perform rapid gait test, could not stand up 5 times from seated position in hardback chair with arms folded, or Fried’s exhaustion criteria | I: frail 22 C: frail 19 | RCT; 12 wk | Mixed; resistance/strength training; 2×/wk; 45 min | Usual care, social meetings | Researcher | Frailty, mobility, physical function (including falls and quality of life) |
| Giné-Garriga et al.,39 2013, Spain | 51 (61/39§) | I: 83.9 ± 2.8 C: 84.1 ± 3 | Fried’s frailty phenotype | I: frail 22 C: frail 19 | RCT; 12 wk | Mixed; resistance/strength training; 2×/wk; duration NR | Usual care, social meetings | NR | Frailty, physical function (including falls and quality of life) |
| Kuo et al.,49 2018, Taiwan | 41 (83/17§) | O: 69.77 I: 68.93 ± 3.81 C: 70.38 ± 5.22 | Comprehensive geriatric assessment | I: frail 15 C: frail 21 | RCT; 8 wk | Aerobic; moderate intensity; 2×/wk; 30 min | Usual care | Researcher | Frailty, mobility, cognitive function, physical function (including falls and quality of life) |
| Kwon et al.,37 2015, Japan | 89 (100/0††) | O: 76.8 I: 77.0 ± 4.2 C: 76.9 ± 3.9 | Fried’s frailty phenotype¶ | I: prefrail 28 C: prefrail 31 | RCT; 12 wk | Mixed; intensity unknown; 1×/wk; 60 min | General health education sessions | Certified health fitness trainer | Frailty, mobility, physical function (including falls and quality of life) |
| Liu et al.,32 2017, Hong Kong | 85 (94/6††) | O: 79.32 ± 7.72 I: 79.72 ± 7.95, 77.03 ± 7.07‡‡ C: 81.90 ± 7.69 | Fried’s frailty phenotype | I: prefrail 5, frail 24 C: prefrail 6, frail 15 | RCT; 16 wk | Mixed; intensity unknown; 1×/wk at centre, 3×/wk at home; 45–60 min at centre, 30–45 min at home | Centre-based health talks on management of various health issues except fatigue | Physiotherapist and exercise instructor | Frailty, mobility, physical function (including falls and quality of life) |
| Liu et al.,30 2018, US | 1635 (66/34§) | I: 78.6 ± 5.2 C: 79.1 ± 5.3 | Study of Osteoporotic Fractures index | NR** | RCT; 2 yr | Mixed; moderate intensity; 3–4×/wk; 50 min | Health education workshops, instructor-led program of gentle upper extremity stretching or flexibility exercises | NR | Frailty, mobility |
| Losa-Reyna et al.,29 2019, Spain | 30 (75/25§) | O: 84.2 ± 4.5 I: 84.0 ± 4.7 C: 84.4 ± 4.6 | Fried’s frailty phenotype | O: prefrail 7, frail 13 | CCT; 6 wk | Mixed; high/strenuous intensity; 2×/wk; 45 min | Usual care | NR | Frailty, mobility, physical function (including falls and quality of life) |
| Ng et al.,36,60,61 2015, Singapore | 246 (56/44††) | O: 70.0 ± 4.7 I: 69.7 ± 4.23, 69.7 ± 4.31, 70.3 ± 5.25, 70.4 ± 4.74‡‡ C: 70.1 ± 5.02 | Cardiovascular Health Study criteria | I: prefrail 29, frail 19 C: prefrail 43, frail 7 | RCT; 24 wk | Mixed; resistance/strength training; 2×/wk; 90 min | Standard care | Qualified trainer | Frailty, mobility, cognitive function, physical function (including falls and quality of life), use of health care services |
| Takatori et al.,34 2016, Japan | 266 (100/0) | O: 75 ± 5 I: 74.6 ± 5.1 C: 75.9 ± 6.0 | Kihon Checklist | I: frail 148 C: frail 118 | CCT; 6 mo | Muscle-strengthening; intensity unknown; 3×/wk; 5 min | Maintained or improved activity in daily life, lectures on health | Physiotherapist, then self-guided | Frailty, mobility, physical function (including falls and quality of life) |
| Tarazona-Santabalbina et al.,35 2016, Spain | 100 (54/46) | I: 79.7 ± 3.6 C: 80.3 ± 3.7 | Fried’s frailty phenotype | I: frail 51 C: frail 49 | RCT; 24 wk | Mixed; moderate intensity; 5×/wk; 65–70 min | Usual care | Physiotherapist and nurse | Frailty, mobility, cognitive function, physical function (including falls and quality of life), use of health care services |
| Tieland et al.,38 2015, the Netherlands | 127 (61/29) | O: 79.0 ± 0.7 I: 78.4 ± 1.0 C: 79.5 ± 1.0 | Fried’s frailty phenotype | I: prefrail 84%, frail 16% C: prefrail 72%, frail 28% | CCT; 24 wk | Muscle-strengthening; resistance/strength training; 2×/wk; duration NR | Usual care | Personal supervision | Frailty, mobility, physical function (including falls and quality of life) |
| Tsang et al.,50 2013, China | 134 (75/25§) | I: 83.33 ± 6.30 C: 84.85 ± 6.03 | 62-item frailty index | I: frail 61 C: frail 55 | RCT; 12 wk | Mobility/rehabilitation; light intensity; frequency NR; 60 min | Newspaper reading and discussion activity | Certified qigong instructor | Frailty, mobility, cognitive function |
| Yamada et al.,53 2012, Japan | 610 (77/23) | I: 79.7 ± 6.3 C: 80.3 ± 6.6 | Frailty checklist of Japan | Mean total score on frailty checklist ± SD: I: 7.41 ± 3.98 C: 7.34 ± 4.27 | Prospective cohort study; 16 wk | Mixed; moderate intensity; 1×/wk; 90 min | Screening evaluation | Physiotherapist | Frailty |
| Yamada et al.,52 2017, Japan | 3240 (82/18) | I: 77.1 ± 6.4 C: 77.2 ± 6.9 | Kihon Checklist | I: prefrail 591, frail 420, robust 609 C: prefrail 591, frail 420, robust 609 | Prospective cohort study; 4 yr | Mixed; light intensity; 1×/wk; 60 min | Matched on all baseline characteristics (e.g., age, gender, body mass index) and each item on Kihon Checklist | Volunteer staff | Frailty |
| Yarasheski et al.,47 1999, US | 17 (71/29) | I: female 82 ± 2, male 82 ± 1 C: female 82 ± 2, male: 82§§ | Physical Performance Test, self-reported ADLs | I: mild to moderate frailty 12 C: mild to moderate frailty 5 | RCT; 9 mo | Muscle-strengthening; resistance/strength training; 3×/wk; duration NR | Home exercises (primarily flexibility), monthly exercise sessions | NR | Frailty, physical function (including falls and quality of life) |
| Yoon et al.,33 2018, South Korea | 65 (70/30§) | O: 73.94 ± 4.27 I: 73.82 ± 4.37 C: 74.03 ± 4.27 | Cardiovascular Health Study criteria | Mean frailty criteria ± SD: I: 1.63 ± 0.90 C: 1.37 ± 0.56 | RCT; 16 wk | Muscle-strengthening; resistance/strength training; 3×/wk; 60 min | Usual care, dynamic stretching | Exercise instructor | Frailty, mobility, cognitive function, physical function (including falls and quality of life) |
Note: ADL = activity of daily living, C = control, CCT = clinical controlled trial, F = female, I = intervention, M = male, NR = not reported, O = overall, RCT = randomized controlled trial, SD = standard deviation.
↵* Fried’s frailty criteria were derived from the Cardiovascular Health Study (CHS) and as such can be considered the same as the CHS criteria; however, we report here how the assessment tool was described by the study authors.
↵† Total nonfrail, prefrail and frail for entire study population by intervention and control groups (may include multiple treatment arms combined).
↵‡ Not including follow-up, if applicable.
↵§ Values based on reported baseline, which may not equal the number randomly allocated but, rather, the number who completed the intervention.
↵¶ Authors indicated that the assessment tool was modified.
↵** Authors indicated that most participants were frail; however, the number of frail participants was unclear.
↵†† The n from the most relevant intervention/treatment arms was used to calculate proportions.
↵‡‡ Only 1 intervention group met the inclusion criteria for this review.
↵§§ Only 1 participant.