Self-reported disability: association with lower extremity performance and other determinants in older adults attending primary care

Abstract

Background. Measurement of function usually involves the use of both performance-based and self-report instruments. However, the relationship between both types of measures is not yet completely understood, in particular for older adults attending primary care. Objective. The main objective of the study was to investigate the association between the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) and the Short Physical Performance Battery (SPPB) for older adults at primary care. A secondary objective was to determine the influence of sociodemographic and health-related variables on this relationship. Design. This was a cross-sectional study. Methods. A total of 504 participants aged 60 years and older from 18 different primary care centers underwent a one-session assessment including: sociodemographic variables, comorbidities, performance, self-reported disability, pain, depressive symptoms, and physical activity. Performance was assessed using the SPPB, and self-reported disability was assessed using the WHODAS 2.0. Results. The correlation between WHODAS 2.0 and SPPB scores was strong (r=.65). Regression analysis showed that the SPPB total score explained 41.7% of the variance in WHODAS 2.0 scores (adjusted R2=41.6%). A second model including the SPPB subtests (balance, gait, and sit-to-stand), depressive symptoms, number of pain sites, pain intensity, and level of physical activity explained 61.7% of the variance in WHODAS 2.0 scores (adjusted R2=60.4%). No model improvement was found when considering the 6 WHODAS 2.0 individual domains. Limitations. The cross-sectional nature of the study does not allow inferences on causal relationships. Conclusions. This study's findings confirm that self-report and performance-based measures relate to different aspects of functioning. Further study is needed to determine if primary care interventions targeting lower extremity performance and depressive symptoms improve self-reported disability.