Chest
Volume 144, Issue 1, July 2013, Pages 119-127
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Original Research
COPD
Cognitive Dysfunction in Patients Hospitalized With Acute Exacerbation of COPD

https://doi.org/10.1378/chest.12-2099Get rights and content

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.

Section snippets

Study Design

Three groups were recruited prospectively with written consent: (1) patients prior to discharge following hospitalization with acute exacerbation of COPD (n = 30); (2) individuals with stable, nonexacerbating COPD, (n = 50); and (3) locally recruited, healthy control subjects (n = 30). The study was undertaken at St. George's University and St. George's National Healthcare Trust, London, England. Favorable ethical opinion was provided by the Wandsworth and East Central London Research Ethics

Demographic Data

There was no significant difference between the two COPD groups in age, sex, or pack-years smoked. The COPD-E group had worse lung function and SGRQ scores, was relatively more hypoxemic, and had a higher cerebrovascular risk score (Tables 3, 4). Overall, control subjects had a higher education level than both COPD groups and smoked less (Table 5), but the groups did not differ in terms of age or sex. In the COPD-E group, length of stay (LOS) was 7.9 days (range, 1-45 days); four patients

Discussion

This study has shown that patients with COPD who are judged medically fit for discharge following an exacerbation have significant deficits in cognitive function. One-half of the COPD-E group in our study had at least mild impairment of processing speed, and in a significant proportion, the loss was in the pathologic range. These deficits appear to have been acquired at some point in the patient's life, and showed no sign of recovery when assessed 3 months later. The degree of deficit was

Conclusions

Patients awaiting discharge from hospital following an acute exacerbation of COPD have clinically significant, but currently unrecognized, cognitive deficits. It is unclear whether these are acute, chronic, or reversible, but they appear to be related to impaired health. Clinicians should be alert to the impact of these cognitive difficulties in the acute and chronic management of COPD.

Acknowledgments

Author contributions: All authors had full access to the data in the study. Dr Jones takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Dodd: contributed to the study concept and design, participant recruitment, data collection and analysis, and writing the manuscript and also served as principal author.

Dr Charlton: contributed to participant recruitment, data collection and analysis, and writing the manuscript.

Dr van den Broek: contributed to the study

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    Funding/Support: This research was supported by an unrestricted research grant from GlaxoSmithKline plc.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

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