Association between cognitive declines and disability in activities of daily living in older adults with COPD: evidence from the China health and retirement longitudinal study

OBJECTIVES: This study aimed to investigate the relationship between disability and domain-specific cognitive function in older adults with chronic obstructive pulmonary disease (COPD). DESIGN: Cross-sectional analyses combined with retrospective longitudinal analyses. SETTING: We included 450 communities in China. PARTICIPANTS: In this study, 1022 (mean age: 68.6±6.3; 612 males) and 152 (mean age: 67.0±5.2; 83 males) older adults with COPD from the China Health and Retirement Longitudinal Study were included in a cross-sectional multivariate linear regression analysis and a longitudinal logistic regression analysis, respectively. OUTCOME MEASURES: Disability was determined by the difficulty or inability to complete 1 of the 12 activity items in basic activities of daily living (ADL) and instrumental ADL. The cognitive dimensions of episodic memory, attention/numerical ability, orientation to time, and visuospatial ability were assessed via the immediate/delayed recall task, serial sevens task, naming the current date and pentagon-figure-drawing tasks, respectively. RESULTS: Of 1022 older respondents with COPD at wave-4, 48.5% had ADL disability. Declines in the global cognitive function (β (95% CI)=−0.627 (−1.214 to –0.040)), orientation to time (β (95% CI)=−0.207 (−0.364 to –0.050)) and visuospatial ability (β (95% CI)=−0.068 (−0.127 to –0.009)) were significantly associated with the presence of ADL disability, when demographic and health-related variables were adjusted. Of 152 older participants with COPD and without ADL disability in wave-2, 61 (40.1 %) developed disability over a 2-year follow-up. Relative to the participants without a decline in orientation to tine, those with the condition had greater odds of incidence of ADL disability increased by a factor of about 1.46 over a 2-year follow-up. CONCLUSIONS: In older adults with COPD, orientation to time and visuospatial inability are vulnerable to the presence of a disability. Prevention of a decline in orientation to time might help prevent disability in older people with COPD.