Development and validation of an intrinsic capacity composite score in the Longitudinal Aging Study Amsterdam: a formative approach

Intrinsic capacity: an under-researched concept in geriatrics

In 2015, the World Health Organisation (WHO) introduced the concept of intrinsic capacity (IC) as part of a new public health model for healthy ageing. IC refers to the overall combination of an individual's physical and mental capacities, and is promoted as a new positive approach to the health and wellbeing of older adults. However, there is still insufficient evidence that implementing IC leads to better care for older adults. Moreover, the current operationalisations of IC lead to confusion and redundant research. In this commentary, we discuss whether the concept of IC has added value for geriatrics, and describe the main issues related to its conceptualisation, measurement, and application. We argue that there is a need to clarify and validate the concept of IC, including independent evidence regarding its feasibility and acceptance in clinical practice.

Association between Muscle Fatigability, Self-Perceived Fatigue and C-Reactive Protein at Admission in Hospitalized Geriatric Patients

Background: The capacity to perceived vitality (CPV) ratio is a novel measure for intrinsic capacity or resilience based on grip work and self-perceived fatigue. CPV has been associated with pre-frailty in older adults and post-surgery inflammation in adults. To better understand the utility of this measure in a frail population, we examined the association between CPV and inflammation in geriatric inpatients. Methods: Data were obtained from 104 hospitalized geriatric patients. The average age of participants was 83.3 ± 7.5 years, and 55.8% of participants were women. In the cross-sectional analyses, associations between C-reactive protein (CRP), grip work (GW), self-perceived fatigue (SPF) and the CPV ratio (higher values indicate better capacity) were examined using linear regression adjusted for confounders. Results: The adjusted association between CRP (abnormal vs. normal) and the CPV ratio was not statistically significant (B = -0.33, 95% CI = -4.00 to 3.34). Associations between CRP and GW (B = 25.53, 95% CI = -478.23 to 529.30) and SPF (B = 0.57, 95% CI = -0.64 to 1.77) were also not statistically significant. Similar results were found in unadjusted models and analyses of cases with complete data. Conclusions: In this frail group of geriatric inpatients, inflammation, routinely assessed with CRP, was not associated with CPV or its components, GW and SPF. Further research is needed to explore whether CPV is a useful indicator of frailty or recovery capacity in hospitalized geriatric patients.

The icope Intrinsic Capacity Screening Tool: Measurement Structure and Predictive Validity of Dependence and Hospitalization

OBJECTIVES

To evaluate the measurement structure of the ICOPE screening tool (IST) of intrinsic capacity and to find out whether the IST as a global measure adds explanatory power over and above its domains in isolation to predict the occurrence of adverse health outcomes such as dependence and hospitalization in community-dwelling older people.

DESIGN

Secondary analysis of a cohort study, the Toledo Study of Healthy Ageing.

SETTING

Province of Toledo, Spain.

PARTICIPANTS

Community-dwelling older people.

MEASUREMENTS

Items equal or similar to those of the IST were introduced as a reflective-formative construct in a Structural Equation Model to evaluate its measurement structure and its association with dependence for basic and instrumental activities and hospitalization over a three-year period.

RESULTS

A total of 1032 individuals were analyzed. Mean age was 73.5 years (sd 5.4). The least preserved indicators were ability to recall three words (18%) and to perform chair stands (54%). Vision and hearing items did not form a single sensory domain, so six domains were considered. Several cognition items did not show sufficiently strong and univocal associations with the domain. After pruning the ill-behaved items, the measurement model fit was excellent (Satorra-Bentler scaled chi-square: 10.3, degrees of freedom: 11, p=0.501; CFI: 1.000; RMSEA: 0.000, 90% CI: 0.000-0.031, p value RMSEA<=0.05: 1; SRMR: 0.055). In the structural model, the cognition domain items were not associated as expected with age (p values 0.158 and 0.293), education (p values 0.190 and 0.432) and dependence (p values 0.654 and 0.813). The IST included as a composite in a model with the individual domains showed no statistically significant associations with any of the outcomes (dependence for basic activities: 0.162, p=0.167; instrumental: -0.052, p=0.546; hospitalization: 0.145, p=0.167), while only the mobility domain did so for dependence (basic: -0.266, p=0.005; instrumental: -0.138, p=0.019). The model fit of the last version was good (Satorra-Bentler scaled chi-square: 52.1, degrees of freedom: 52, p=0.469; CFI: 1.000; TLI: 1.000; RMSEA: 0.01, 90% CI: 0.000-0.02, p value RMSEA<=0.05: 1; SRMR: 0.071). The IST operationalized as the sum of non-impaired domains was not associated after covariate adjustment (dependence for basic activities: -0.065, p=0.356; instrumental: -0.08, p=0.05; hospitalization: -0.003, p=0.949) either.

CONCLUSION

The cognitive domain of the IST, and probably other of its items, may need a reformulation. A global measure of intrinsic capacity such as the IST does not add explanatory power to the individual domains that constitute it. So far, our results confirm the importance of checking the findings of the IST with a second confirmatory step, as described in the WHO's ICOPE strategy.