Rationale Cognitive impairment is one of the least well-studied COPD comorbidities. It occurs in a proportion of hypoxemic patients, but its presence during acute exacerbation has not been established. We assessed neuropsychological performance in patients awaiting discharge from hospital following acute exacerbation and compared them to healthy controls and stable normoxic outpatients with COPD.
Methods 109 participants were recruited: 29 COPD in-patients medically fit and awaiting discharge following an exacerbation (COPD-E), 50 stable COPD patients (COPD-S), and 30 controls. Neuropsychological tests measured performance in episodic memory, executive function, working memory, visuo-spatial function, processing speed and an estimate of premorbid abilities.
Results Unrecognised, moderate to severe impairment was found in over half of COPD-E with the most frequent impairment in immediate verbal episodic memory (55%), delayed visual episodic memory (54%), executive function (52%), working memory (52%), visuo-spatial function (50%) and processing speed (48%). Post hoc analysis confirmed COPD-E group observations were significantly low (p<0.05; Abstract P41 table 1). COPD-E were significantly worse than COPD-S patients in episodic and working memory independent of premorbid ability, hypoxaemia, disease severity, cerebrovascular risk or pack years smoked. In addition 20% of COPD-E demonstrated an acquired pathological loss in processing speed.
Conclusion Around half of patients with acute exacerbation were discharged home with unrecognised moderate to severe cognitive impairment. Patients with an acute exacerbation have worse episodic and working memory than stable patients and appear to have an acquired loss in processing speed. It is unclear whether this loss is acute, chronic or reversible.