As Singapore’s population rapidly ages, there is a growing need to proactively address frailty and intrinsic capacity (IC) decline to delay disability and preserve independence. This study aims to a) determine prevalence of IC decline in frail older patients referred to the geriatric service hub (GSH), stratified by age and frailty status and b) determine its association with activity of daily living (ADL).

A cross-sectional study was conducted from July 2019 to March 2022. Community-dwelling older adults (≥65 years) identified as pre-frail or frail in selected primary care clinics and eldercare centers were referred to the GSH for further evaluation. All participants received a comprehensive geriatric assessment, which included Clinical Frailty Scale (CFS) scoring and evaluation of six IC domains: locomotion, vitality, cognition, sensory (vision and hearing), psychological, and continence. Functional status was assessed using the Modified Barthel Index and self-reported ADL and instrumental ADL (IADL).

Among 372 participants, 52.2 % were aged 65–79 (old) and 47.8 % were ≥ 80 years (old-old). Approximately two-thirds were classified as CFS 4 or 5. IC decline was significantly more prevalent in the “old-old” group, especially in locomotion (94.4 %), vitality (94.5 %), cognition (68.4 %), vision (78.7 %), and hearing (33.1 %). Despite IC decline, up to two-thirds of participants remained independent or only mildly dependent in ADL. IC impairment increased progressively with advancing frailty and age. In multivariate logistic regression, moderate to severe ADL dependency was independently associated with impaired locomotion (aOR 5.105; 95 % CI 1.023–25.477) and vision impairment (aOR 2.607; 95 % CI 1.234–5.508).

IC screening in primary care is a feasible and effective approach that may contribute to detection of early functional decline. The high burden of multidomain IC impairment, particularly among the oldest and most frail, supports the need for upstream, integrated, and age-inclusive screening and intervention strategies in community settings.