Disparity between capacity and performance in the International Classification of Functioning: implications for functionality in older adults

Abstract

Abstract: Background: Functioning, recognized as the third health indicator and a key metric for rehabilitation, can be assessed by measuring capacity and performance. Objective: To quantify the prevalence of disability and cognitive impairment in individuals aged 50+ and evaluate the reliability and clinical relevance of capacity and performance qualifiers in the activity and participation domains of the international classification of functioning checklist (ICF checklist). Methods: A cross-sectional study was conducted in a population from rural and urban areas of Aragón (Spain), including 1707 participants. Disability and cognitive impairment were assessed using the WHO Disability Assessment Schedule 12-item version (WHODAS 12) and mini-mental state examination. A randomly selected subsample (n = 129) underwent a detailed functional evaluation. The ICF checklist was used to compare capacity and performance, analyzing their agreement and differences. Results: Disability was present in 50.6% of participants. Severe or total disability was most prevalent in general tasks/demands (10.1%) and domestic life (7.1%), reflecting significant daily functioning limitations. The largest capacity-performance discrepancies were in domestic life, self-care, and learning, indicating key intervention areas. Notably, 40.5% of participants had lower performance in domestic life, followed by learning/knowledge (28%) and mobility (17%). Conversely, performance exceeded capacity in community living (13.3%) and personal relationships (5.5%), highlighting the influence of environmental factors. Conclusions: Disability is highly prevalent in adults aged 50+, notably affecting daily functioning. Gaps between ability and performance indicate environmental barriers, especially at home and in learning contexts. Improved outcomes in social domains suggest enabling conditions. Findings support the ICF checklist’s clinical value and advocate for integrating environmental factors into disability care.