Purpose: We investigated the association between cognitive impairment and chronic obstructive pulmonary disease (COPD), taking into account demographic and clinical variables evaluated during routine practice.
Patients and methods: We performed a post hoc analysis of a cross-sectional study that included subjects with stable COPD. Sociodemographic and clinical information was recorded using the Body mass index, airflow Obstruction, Dyspnea and Exacerbations index and the Charlson comorbidity index. Cognitive performance was studied by the mini-mental state examination, with a score less than 27 indicating clinical impairment. Depressive symptoms, physical activity, and quality of life (EuroQoL-5 dimensions and COPD Assessment Test) were also evaluated.
Results: The analysis included 940 subjects. The prevalence of cognitive impairment was 39.4%. Multivariate logistic regression models revealed that cognitive impairment was associated with educational level (odds ratio [OR] =0.096, 95% confidence interval [CI] =0.011-0.447) and poorer quality of life measured by the EuroQoL-5 dimensions social tariff (OR =0.967, 95% CI =0.950-0.983). When questionnaires were not included in the analysis, cognitive impairment was associated with educational level (OR =0.063, 95% CI =0.010-0.934), number of exacerbations (OR =11.070, 95% CI =1.450-84.534), Body mass index, airflow Obstruction, Dyspnea and Exacerbations index score (OR =1.261, 95% CI =1.049-1.515), and the Charlson comorbidity index (OR =1.412, 95% CI =1.118-1.783).
Conclusion: Cognitive impairment is common in COPD and is associated with low educational level, higher disease severity, and increased comorbidity. This could have therapeutic implications for this population.
Keywords: chronic obstructive pulmonary disease; cognitive function; comorbidity; depression; mini-mental state examination; quality of life.