Examining the Relationship Between COPD and Cognitive Impairment

There is a correlation between chronic obstructive pulmonary disease (COPD) and cognitive impairment, but the extent has not previously been accurately determined. Studies have shown anywhere from 12% to 88% incidence of cognitive impairment in COPD patients.

However, the recent COgnitive-PD (Cognitive Pulmonary Disease) study set out to conduct an in-depth examination of patients suffering from COPD and its correlation to irregularities in the brain [BMJ Open. 2014;4:e004495]. Previously, cognitive functioning studies focused on broad scale measurements that did not separate specific cognitive functions.

This ongoing study, taking place between November 2013 and November 2015, includes patients who enter CIRO+ pulmonary rehabilitation program. There will be 183 participants who have been diagnosed with COPD taking part in the study. The 183 COPD patients will be paired with one of the 90 healthy control participants whom they are similar to in age, education, and smoking status; thus, creating small groups of participants with similar clinical characteristics and demographics. In addition, to perform an MRI substudy, there will be a subgroup of 35 participants with COPD but no cognitive impairment and 35 patients with COPD and cognitive impairment. This will determine what, if any, brain abnormalities exist in patients with COPD that do and do not have cognitive impairment. Monitoring will be carried out by CIRO+ healthcare professionals once a year.

There are 5 primary objectives of this study: (1) determine whether or not and to what extent the cognitive functioning of a patient with COPD is impaired in cognitive flexibility, memory, planning, and psychomotor speed; (2) examine the characteristics, clinical and demographical, of patients with COPD and cognitive impairment; (3) examine whether or not and to what extent COPD affects the daily functioning of patients; (4) determine whether or not and to what extent cognitive functioning alters patient outcomes of pulmonary rehabilitation (eg, insight on COPD, basic psychological functioning, etc); and (5) conclude whether or not and to what extent, in COPD patients with cognitive impairment and without cognitive impairment, the existence of structural and functional brain abnormalities.   

Researchers expect to find that COPD patients that experience severe airflow limitation exhibit the lowest overall cognitive functioning capacity. Researchers theorize patients with COPD encounter worse cognitive functioning than participants without COPD. They also believe that findings will show patients that have cognitive impairment, compared to patients with COPD and no cognitive impairment, will bear disadvantages in daily functioning, worse clinical characteristics, and worse pulmonary rehabilitation results. The researchers also theorized that COPD patients who exhibit brain abnormalities have cognitive impairments and disadvantages in daily functioning.

This study will possess advantages that previous studies did not. The COgnitive-PD study will utilize innovative imaging techniques and extensive multineuropsychological testing unlike previous studies that used a single scale to determine cognitive function. These imaging techniques and neuropsychological testing will allow researchers to sufficiently illustrate cognitive functioning in definitive areas including data on functional connections and structural connections.

The COgnitive-PD study may experience some limitations. The comparison between patients with COPD and the control group may be impacted by characteristics and/ or demographics that are not covered in the study. The study will not allow for definite conclusions on casual relationships (eg, cognitive functioning and comorbidities) as a result of cross-sectional assessment of cognitive functioning. Finally, these results are limited to patients admitted to CIRO+ pulmonary rehabilitation program and not necessarily representative of COPD patients as a whole.  

Due to extensive testing, the COgnitive-PD study will provide specific data on cognitive impairment in patients with COPD that were committed to CIRO+ pulmonary rehabilitation program. The conclusions from this study could assist with modifying pulmonary rehabilitation programs as well as disease management programs to better fulfill the needs and abilities of COPD patients who are cognitively impaired.