Table 5. Main characteristics of studies evaluating the cost-effectiveness of physical activity interventions.
| No. | Study | Intervention description and comparator (Setting) | Country | Type of study and economic evaluation (Time horizon) | Sample size No. PwDs/No. Caregivers (Intervention Group/Control Group) |
Perspective | PwD outcome measures | Caregiver outcome measures | Incremental Cost-Effectiveness Ratio (ICER) and other cost-effectiveness measures | Cost-effectiveness assessment | Cost-effectiveness rationale | Quality of the study |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Eckert et al. 2021 [126] | Individually-tailored exercise program vs unspecified flexibility training (Community-based: home) |
Germany | RCT CEA+CUA (24 weeks) |
118 / 0 (63 / 55) |
Societal |
|
— | 92% probability of positive net monetary benefit for a WTP of €500 per point on the SPPB; 90% probability of cost-utility for a WTP of €20,000 per QALY (no QALY gains but lower healthcare costs in the intervention group) |
Moderate | Partial cost-effectiveness: high probability of cost-effectiveness in terms of improved physical performance in geriatric patients with cognitive impairment following discharge from ward rehabilitation, but not in terms of improved quality of life (the exercise intervention did not achieve gains in QALYs compared to control condition). | High |
| 2 | D’Amico et al. 2015 [135] | Physical exercise regimen (walking) for patient-caregiver dyads vs Usual Care (Community-based: home) |
UK | RCT CEA+CUA (12 weeks) |
52 / 52 (30 / 22) |
Health and social care system Societal |
|
|
£421 per NPI point, £286,440 per QALY gained (point estimates with societal perspective) |
Moderate | Partial cost-effectiveness: exercise intervention is significantly cost-effective in terms of improvements in behavioural and psychological symptoms (NPI score), but the authors observe that there is no established cost-effectiveness benchmark for the NPI. Intervention is not cost-effective when considering additional cost of QALY gains. | Medium |
| 3 | Khan et al. 2018 [125] | Structured physical exercise (aerobic and resistance training at moderate-to-hard intensity) vs Usual Care (Community-based: home) |
UK | RCT CUA (12 months) |
494 / 494 (329 / 165) |
Health and social care system Societal |
|
|
Mean ICER negative: -£74,227 per QALY gained (intervention more costly and less effective) |
Low/Absent | Dominated (higher costs and worse outcome). The probability that the exercise intervention is cost effective is < 1% for a WTP between £15,000 and £30,000 for an additional QALY. Patients became physically fitter due to exercise but these benefits did not translate into improvements in important cognitive outcomes. | High |
ADAS-Cog: Alzheimer’s Disease Assessment Scale-Cognition subscale; ADLs: Activities of Daily living; BADLS: Bristol Activities of Daily Living Scale; CSRI: Client Service Receipt Inventory; CUA: Cost-utility analysis; DEMQOL Proxy: Dementia Quality of Life score reported by a carer; EQ-5D: EuroQol-5 Dimensions; GHQ: General Health Questionnaire; MMSE: Mini-Mental State Examination; NPI: Neuropsychiatric Inventory; QALYs: Quality Adjusted Life Years; QoL-AD: Quality of Life-Alzheimer’s Disease scale; RCT: Randomised controlled trial; SPPB: Short Physical Performance Battery; ZBI: Zarit Burden Interview (self-reported questionnaire used to assess carer burden).