Intrinsic Capacity Defined Using Four Domains and Mortality Risk: A 5-Year Follow-Up of the SarcoPhAge Cohort.

Abstract

The concept of 'intrinsic capacity' (IC) offers a new way to approach another concept, that of 'healthy aging'. The first objective of the present study was to assess the ability of the construct of 'intrinsic capacity' to predict death. The second objective was to assess whether deteriorations in intrinsic capacity, measured over 1 and 2 years, are predictive of death. The present analysis was based on a prospective cohort study. Community-dwelling participants. The study recruited older adults aged 65 years and older. Intrinsic capacity (IC) encompasses five domains: sensorial (not evaluated here), cognition (Mini-Mental State Examination), nutrition (Mini-Nutritional Assessment), mobility (Short Physical Performance Battery), and psychological (Geriatric Depression Scale). Each domain was considered satisfactory when its assessment, for an individual, was above the threshold defined by the initial validation of the domain assessment tool. To explore the relationship between IC and mortality risk, a Cox model was applied. The predictive value of the dynamic aspects (i.e., changes over 1 year and 2 years) was investigated using the following categorization of IC: stable, deteriorated, improved. The sample was composed of 481 volunteers aged 73.4±6.12 years (60.1% women). Two satisfactory IC domains appeared to be significantly associated with reduced mortality risk: the satisfactory mobility domain (adjusted HR=0.45 [0.26-0.79]) and the satisfactory psychological domain (adjusted HR = 0.56 [1.04-3.09]). When considering intrinsic capacity as a whole construct, using a composite Z-score, we noticed that the risk of death was decreased by 49% for an increase of 1 standard deviation in IC. Changes in intrinsic capacity in the mobility and psychological domains led to an increased risk of death (from 2.74 to 4.18-fold). The concept of intrinsic capacity seems highly relevant in order to assess older adults' health and well-being. This concept should be considered for integration into clinical practice.