Clinical effects of cognitive impairment in patients with chronic obstructive pulmonary disease

The aim of this study was to evaluate the clinical effects of cognitive impairment in patients with chronic obstructive pulmonary disease (COPD). A total of 91 patients with stable moderate to very severe COPD were included in this study. Cognitive functions of the patients were evaluated using the mini-mental state examination (MMSE) tool and clock-drawing test. The Brody's Instrumental Activities of Daily Living (IADL) Questionnaire; COPD assessment test (CAT); body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE); and Charlson comorbidity index were assessed. The patients were divided into two groups as those who were diagnosed with cognitive impairment (group 1, n = 16) and those with normal cognitive functions (group 2, n = 75). Group 1 had a lower arterial partial pressure of oxygen , shorter 6-min walking distance, and higher arterial partial pressure of carbon dioxide (PaCO₂) than group 2 ( p = 0.01, p = 0.024, p = 0.018, respectively). In group 1, the IADL score was lower, and CAT and BODE scores were higher than group 2 ( p = 0.002, p = 0.037, p = 0.012, respectively). When we considered all the patients, there was an independent correlation between the IADL score and MMSE score ( p = 0.03). This study revealed that COPD patients with cognitive impairment may have more hypoxemia and limited activities of daily living.