Establishment of Clinical Construct of Intrinsic Capacity in Older Adults and Its Prediction of Functional Decline

Abstract

Background The World Health Organization has conceptualised the health and healthcare of older adults around the concept of healthy ageing. Healthy ageing is defined as “the process of developing and maintaining the functional ability that enables well-being in older age”. This functional ability is the sum of two key factors: intrinsic capacity and interacting environment. This concept of intrinsic capacity encompasses a wide spectrum of health characteristics including the physiological and psychological changes associated with the ageing process. In general, IC declines from a high and stable state to an impaired status as people age. Monitoring individuals for changes in intrinsic capacity in the context of their environment will provide a holistic method of tracking the functioning of older adults at both a population and individual level, providing an opportunity to address any reversible factors of decline. However, this would require a clear and objective conceptualisation of the concept of intrinsic capacity. Methodology One hundred subjects were recruited via invitation by advertisement on the institute campus. Study participants underwent detailed physical examination and measurement of various physical and chemical biomarkers which were likely to represent intrinsic capacity as evidenced by the literature review. Outcomes measured were a decline in ADL, IADL, mortality and hospitalisation over a follow-up period of six months. Exploratory factor analysis (EFA) was done to obtain a clinical construct of the proposed entity of intrinsic capacity. Unpaired t -test and univariate logistic regression were used to check for the association between the composite score (IC) and its domains with the decline in ADL, IADL, mortality and hospitalisation. Results One composite score (composite IC score) and eight subfactors emerged. The composite score and subfactor domains showed good construct validity. Composite intrinsic capacity score and subdomains of strength and cognition were significantly different among subjects with and without ADL and IADL decline. Univariate logistic regression showed that composite intrinsic capacity score was a predictor of decline in ADL and IADL even after adjusting for age, sex, comorbidity status and education level of the subject with an adjusted odds ratio of 0.99 and 0.98, respectively. Subdomains of strength and cognition also predicted a decline in ADL and IADL independently. Conclusion The development of an objective construct of the concept of intrinsic capacity, using commonly measured clinical and biochemical parameters, is feasible and predictive of the subsequent functionality of an individual.

Effectiveness of Different Neurocognitive Intervention Approaches on Functionality in Healthy Older Adults: A Systematic Review

“…Therefore, a multi-factorial analysis of aging that comprehends the synergy between different components is essential [2,3]. Several studies [4,5] aim to define the domains of the construct that offer a framework for guiding clinical practice and research regarding intrinsic functional capacity.…”

Prevalence and Factors Associated with Impairment in Intrinsic Capacity among Community-Dwelling Older Adults: An Observational Study from South India

“…Multiple studies from India have reported frailty in hospital and community settings [5][6][7][8]. Few studies from India have recently reported on IC as well [9,10]. Tis study aimed to establish the prevalence of impaired IC among community-dwelling older adults aged ≥60 and the prevalence of impairment in each domain.…”

Associations between intrinsic capacity, functional difficulty, and fall outcomes among older adults in India

“…Several studies worldwide, most in high-income western nations and some in LMICs, have explored the concept of IC and its association with social, economic, and lifestyle factors, and a variety of health outcomes. Only one study 43 has assessed the relevance of IC for functional decline among older adults in India. However, this study was limited to the outcomes of ADL and IADL and the sample size was small preventing the otherwise important findings of the study from being extrapolated.…”