Economic models of community-based falls prevention: a systematic review with subsequent commissioning and methodological recommendations

Incorporating frailty to address the key challenges to geriatric economic evaluation

BACKGROUND

The multidimensional and dynamically complex process of ageing presents key challenges to economic evaluation of geriatric interventions, including: (1) accounting for indirect, long-term effects of a geriatric shock such as a fall; (2) incorporating a wide range of societal, non-health outcomes such as informal caregiver burden; and (3) accounting for heterogeneity within the demographic group. Measures of frailty aim to capture the multidimensional and syndromic nature of geriatric health. Using a case study of community-based falls prevention, this article explores how incorporating a multivariate frailty index in a decision model can help address the above key challenges.

METHODS

A conceptual structure of the relationship between geriatric shocks and frailty was developed. This included three key associations involving frailty: (A) the shock-frailty feedback loop; (B) the secondary effects of shock via frailty; and (C) association between frailty and intervention access. A case study of economic modelling of community-based falls prevention for older persons aged 60 + was used to show how parameterising these associations contributed to addressing the above three challenges. The English Longitudinal Study of Ageing (ELSA) was the main data source for parameterisation. A new 52-item multivariate frailty index was generated from ELSA. The main statistical methods were multivariate logistic and linear regressions. Estimated regression coefficients were inputted into a discrete individual simulation with annual cycles to calculate the continuous variable value or probability of binary event given individuals' characteristics.

RESULTS

All three conceptual associations, in their parameterised forms, contributed to addressing challenge (1). Specifically, by worsening the frailty progression, falls incidence in the model increased the risk of falling in subsequent cycles and indirectly impacted the trajectories and levels of EQ-5D-3 L, mortality risk, and comorbidity care costs. Intervention access was positively associated with frailty such that the greater access to falls prevention by frailer individuals dampened the falls-frailty feedback loop. Association (B) concerning the secondary effects of falls via frailty was central to addressing challenge (2). Using this association, the model was able to estimate how falls prevention generated via its impact on frailty paid and unpaid productivity gains, out-of-pocket care expenditure reduction, and informal caregiving cost reduction. For challenge (3), frailty captured the variations within demographic groups of key model outcomes including EQ-5D-3 L, QALY, and all-cause care costs. Frailty itself was shown to have a social gradient such that it mediated socially inequitable distributions of frailty-associated outcomes.

CONCLUSION

The frailty-based conceptual structure and parameterisation methods significantly improved upon the methods previously employed by falls prevention models to address the key challenges for geriatric economic evaluation. The conceptual structure is applicable to other geriatric and non-geriatric intervention areas and should inform the data selection and statistical methods to parameterise structurally valid economic models of geriatric interventions.

Interaction between cognitive and motor disorders for risk screening of incident falls: results of an elderly population-based observational cohort study

BACKGROUND

This study aims to examine (1) the association of "Emergency Room Evaluation and Recommendations" (ER²) cognitive and motor items with incident falls (i.e., ≥ 1), their recurrence (i.e., ≥ 2) and post-fall fractures and (2) the performance criteria (i.e., sensitivity, specificity) of the greater identified association for each incident fall outcome in older community dwellers.

METHODS

7147 participants (80.5 ± 3.8; 100% female) of the EPIDémiologie de l'OStéoporose (EPIDOS) observational population-based cohort study were recruited in France. Inability to name the day's date and the use of a walking aid and/or an history of falls were recorded at baseline. Incident outcomes, which were ≥ 1 fall,  ≥ 2 falls and post-fall fractures, were collected every 4 months over a period of 4 years.

RESULTS

The overall incidence of ≥ 1 fall was 26.4%, 6.4% for ≥ 2 falls, and 19.1% for post-fall fractures. Cox regressions revealed that the use of a walking aid and/or an history of falls [Hazard ratio (HR) ≥ 1.03 with P ≤ 0.011], inability to name the day's date (HR ≥ 1.05 with P ≤ 0.003), and their combination (HR ≥ 1.37 with P ≤ 0.002) were significantly associated with both incident falls, regardless of their recurrence, and post-fall fractures.

INTERPRETATION

A significant positive association between ER² cognitive and motor items, both, respectively, and in combination, with an overall incidence of falls, regardless of their recurrence, as well as with post-fall fractures was demonstrated. However, the low sensitivity and high specificity of the combination of ER² items suggest that these items cannot be used for risk screening of fall outcomes in the older population.

Economic model of community-based falls prevention: seeking methodological solutions in evaluating the efficiency and equity of UK guideline recommendations

Background

Falls significantly harm geriatric health and impose substantial costs on care systems and wider society. Decision modelling can inform the commissioning of falls prevention but face methodological challenges, including: (1) capturing non-health outcomes and societal intervention costs; (2) considering heterogeneity and dynamic complexity; (3) considering theories of human behaviour and implementation; and (4) considering issues of equity. This study seeks methodological solutions in developing a credible economic model of community-based falls prevention for older persons (aged 60 +) to inform local falls prevention commissioning as recommended by UK guidelines.

Methods

A framework for conceptualising public health economic models was followed. Conceptualisation was conducted in Sheffield as a representative local health economy. Model parameterisation used publicly available data including English Longitudinal Study of Ageing and UK-based falls prevention trials. Key methodological developments in operationalising a discrete individual simulation model included: (1) incorporating societal outcomes including productivity, informal caregiving cost, and private care expenditure; (2) parameterising dynamic falls-frailty feedback loop whereby falls influence long-term outcomes via frailty progression; (3) incorporating three parallel prevention pathways with unique eligibility and implementation conditions; and (4) assessing equity impacts through distributional cost-effectiveness analysis (DCEA) and individual-level lifetime outcomes (e.g., number reaching ‘fair innings’). Guideline-recommended strategy (RC) was compared against usual care (UC). Probabilistic sensitivity, subgroup, and scenario analyses were conducted.

Results

RC had 93.4% probability of being cost-effective versus UC at cost-effectiveness threshold of £20,000 per QALY gained under 40-year societal cost-utility analysis. It increased productivity and reduced private expenditure and informal caregiving cost, but productivity gain and private expenditure reduction were outstripped by increases in intervention time opportunity costs and co-payments, respectively. RC reduced inequality delineated by socioeconomic status quartile. Gains in individual-level lifetime outcomes were small. Younger geriatric age groups can cross-subsidise their older peers for whom RC is cost-ineffective. Removing the falls-frailty feedback made RC no longer efficient or equitable versus UC.

Conclusion

Methodological advances addressed several key challenges associated with falls prevention modelling. RC appears cost-effective and equitable versus UC. However, further analyses should confirm whether RC is optimal versus other potential strategies and investigate feasibility issues including capacity implications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-023-03916-z.