Current and Former Smokers With COPD Have Risk for Cognitive Impairment

After careful consideration, the American Thoracic Society canceled its annual meeting that was to take place in Philadelphia, Pennsylvania from May 15-20, because of the ongoing coronavirus disease 2019 (COVID-19) pandemic. Although the live events will not proceed as planned, our readers can still find coverage of research that was scheduled to be presented at the meeting. A virtual event is being planned for later this year.

Approximately 1 in 4 current and former smokers with chronic obstructive pulmonary disease (COPD) are at risk for mild cognitive impairment and dementia according to findings intended to be presented at the American Thoracic Society (ATS) International Conference. (Select research is slated to be presented in a virtual format later this year.)

While previous research has established the increased risk for mild cognitive impairment and dementia in patients with COPD, recent awareness regarding the prevalence and significance of respiratory impairments in Global Initiative for Chronic Obstructive Lung Disease (GOLD) and Preserved Ratio Impaired Spirometry (PRISm) suggests smokers with an forced expiratory volume in 1 second/forced vital capacity (FEV₁/FVC) ratio >0.7 may also be at risk for cognitive impairment.

In this study, investigators examined cognitive impairment across all smokers (n=997; ≥10 pack-years) using data from the multisite COPDGene study (ClinicalTrials.gov Identifier: NCT00608764). Participants completed the MiniCog in phase 3 of the study, and cognitive impairment (MiniCog+) was defined as a total score of ≤3.

In order to focus on smokers whose FEV₁/FVC ratio was >0.7 (based on GOLD 0 and PRISm), researchers used a logistic regression to identify pulmonary measures associated with cognitive impairment. Using MiniCog+ status as the dependent variable, researchers also analyzed age, sex, race, education, pack-years, lung function (postbronchodilator FEV₁ % predicted), gas trapping (lung attenuation area [LAA]% < -856 HU), emphysema (LAA% <950 HU), and airway wall thickness using standardized airway wall thickness at 10 mm internal perimeter (Pi10) from the most recent lung CT obtained 5 years prior in phase 2 of the study.

Of the individuals studied, the mean age was 69.5 years (49.0% women), 25.2% identified as African American, and mean FEV₁% predicted was 77.8 (41.4% GOLD 0; 11.4% PRISm; 11.2% GOLD 1; 35.9% GOLD 2-4). Researchers reported that the frequency of MiniCog+ status varied across groups (14.3% GOLD 0; 32.5% PRISm 20.5%; GOLD 1 26.3%; GOLD 2-4; Chi-square=25.8; P <.001).

Variables independently associated with MiniCog status in GOLD 0 and PRISm smokers via logistic regression were: age (10 years; odds ratio [OR], 1.45; 95% CI, 1.00-2.10), African American race (OR, 3.75; 95% CI, 2.10-6.69), lung function (FEV₁% predicted 10%; OR, 0.80; 95% CI, 0.68-0.94), and CT airway wall thickening (Pi10 OR, 1.83; 95% CI, 1.05-3.21).

The researchers highlighted that current and former smokers with PRISm physiology were at a particularly elevated risk for cognitive impairment, compared to smokers with GOLD 0 spirometry and GOLD 2-4 COPD. They concluded that “future research should focus on determining whether certain phenotypes of smokers with PRISm physiology may be at elevated risk for cognitive impairment.”

Reference

Linkenmeyer C, Comellas AP, Ten Eyck P, et al. Risk for cognitive impairment in smokers with preserved ratio impaired spirometry – an analysis of the COPDGene cohort. Am J Respir Crit Care Med. 2020;201:A6267.

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This article originally appeared on Pulmonology Advisor