Trajectories of change in cognitive function in people with chronic obstructive pulmonary disease

Aims and objectives: To describe changes in cognitive function, as measured by the trail making test; to identify distinct patterns of change in cognitive function; and to examine predictors of change in cognitive function in people with severe chronic obstructive pulmonary disease. Background: How cognitive function changes in people with chronic obstructive pulmonary disease and what factors influence those changes over time is not well known, despite the fact that it declines rapidly in this population and significantly impacts functional decline in healthy older adults. Design: A secondary analysis and longitudinal study with a follow-up period of 3 years. Methods: A data set from the National Emphysema Treatment Trial provided participant data. Patients with severe chronic obstructive pulmonary disease (n = 307) were recruited at a clinical site. Several demographic and clinical measures were assessed at baseline. Trail making test scores were measured at baseline, 1, 2 and 3 years. Results: Cognitive function was stable for 3 years in people with chronic obstructive pulmonary disease. However, four distinct patterns of change in cognitive function were identified. Age, education, 6-min walk distance and cognitive impairment scores at baseline on the trail making test Part B were significant predictors of worsening cognitive function and below-average cognitive function over 3 years. Conclusions: These findings suggest that increasing exercise capacity improves cognitive function and delays deterioration of cognitive function in people with COPD. Relevance to clinical practice: Understanding the trajectories of change in cognitive function and predictors of change in cognitive function over 3 years may enable health care providers to identify patients at greatest risk of developing mental deterioration and those who might benefit from interventions to improve cognitive function. Health care providers should periodically assess and frequently screen people with COPD for cognitive function.