Long-Term Oxygen Therapy and Cognitive Function in Chronic Obstructive Pulmonary Disease: A Systematic Review

Area of Science:

• Pulmonary Medicine
• Neurology
• Geriatrics

Background:

• Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of respiratory morbidity and mortality.
• Cognitive impairment is a common comorbidity in COPD patients, impacting quality of life and treatment adherence.
• Long-term oxygen therapy (LTOT) is a standard treatment for hypoxemic COPD, but its effect on cognition is not fully understood.

Purpose of the Study:

• To evaluate the association between LTOT and cognitive function in COPD patients.
• To synthesize existing evidence on the impact of LTOT on various cognitive domains.

Main Methods:

• Systematic literature search of observational studies comparing cognitive outcomes in COPD patients with and without LTOT (≥15 h/day).
• Cognitive performance assessed using validated tools: Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Trail Making Tests (TMT-A/B).
• Narrative synthesis due to heterogeneity in study designs and outcome measures.

Main Results:

• Five studies with 1849 participants (343 LTOT users) were included.
• LTOT use was associated with a lower prevalence of cognitive impairment (18%-45%) and higher global cognitive scores, particularly in executive functions.
• MoCA scores favored LTOT users, especially in rural populations, though findings showed heterogeneity.

Conclusions:

• LTOT is associated with improved cognitive performance in hypoxemic COPD patients.
• Further prospective longitudinal studies are required to establish causality between LTOT and reduced cognitive impairment in COPD.