Cognitive Functioning Influences Mortality Risk Among Older Adults with COPD

Abstract

Background/Objeectives: Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of mortality in the United States (U.S.), with rates varying by disease severity, comorbidities, and sociodemographic factors. Cognitive impairment has been independently associated with increased mortality, but has not been well studied in relation to COPD despite being a frequently overlooked comorbidity in COPD patients. The purpose of this nationwide study was to assess the relationship between low cognitive performance and the risk of mortality among older adults with COPD while adjusting for major sociodemographic and health-related characteristics. Methods: This study utilized the 1999–2002 National Health and Nutrition Examination Survey (NHANES) and the respiratory mortality data of noninstitutionalized US adults aged over 65 years. Survival curves showing the combined effect of cognitive decline and COPD using the Kaplan–Meier product-limit method to estimate the percent survival of the subject at each point in time were used. Results: The final sample included 2013 older adults, with 39.1% showing low cognitive performance and 12.7% having COPD. Those with low cognitive performance were older, less educated, had lower income, were more likely to be racial/ethnic minorities, and had a history of cardiovascular diseases (CVD); they were also more likely to have COPD or chronic kidney disease (CKD). The adjusted hazard ratio for respiratory-related mortality risk was highest for individuals with both COPD and low cognitive performance (hazards ratio = 8.53), people with COPD alone also had a higher respiratory-related mortality risk (hazards ratio = 4.92), but low cognitive performance alone did not significantly increase respiratory-related mortality risk. Conclusions: These findings provide clearer insights into how cognitive impairment affects mortality risk in older adults with COPD and we discuss potential strategies to address this dual chronic health challenge effectively.