Background: Cognitive impairment is one of the least well-studied COPD comorbidities. It is known to occur in hypoxemic patients, but its presence during acute exacerbation is not established.
Objectives: The purpose of this study was to assess neuropsychological performance in patients with COPD who were awaiting discharge from hospital following acute exacerbation and recovery and to compare them with stable outpatients with COPD and with healthy control subjects.
Methods: We recruited 110 participants to the study: 30 inpatients with COPD who were awaiting discharge following an exacerbation, 50 outpatients with stable COPD, and 30 control subjects. Neuropsychological tests measured episodic memory, executive function, visuospatial function, working memory, processing speed, and an estimate of premorbid abilities. Follow-up cognitive assessments for patients who were stable and those with COPD exacerbation were completed at 3 months.
Results: Patients with COPD exacerbation were significantly worse (P<.05) than stable patients over a range of measures of cognitive function, independent of hypoxemia, disease severity, cerebrovascular risk, or pack-years smoked. Of the patients with COPD exacerbation, up to 57% were in the impaired range and 20% were considered to have suffered a pathologic loss in processing speed. Impaired cognition was associated with worse St. George's Respiratory Questionnaire score (r=-0.40-0.62, P≤.02) and longer length of stay (r=0.42, P=.02). There was no improvement in any aspect of cognition at recovery 3 months later.
Conclusions: In patients hospitalized with an acute COPD exacerbation, impaired cognitive function is associated with worse health status and longer hospital length of stay. A significant proportion of patients are discharged home with unrecognized mild to severe cognitive impairment, which may not improve with recovery.