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

OBJECTIVE: This study is aimed at evaluating the association between long-term oxygen therapy (LTOT) and cognitive function in patients with chronic obstructive pulmonary disease (COPD). METHODS: We conducted a systematic literature search across major databases for observational studies comparing cognitive outcomes between COPD patients receiving LTOT (≥ 15 h/day) and those not receiving it. Cognitive performance was evaluated using validated tools like the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Trail Making Tests (TMT-A/B). Due to heterogeneity in study design and outcome measures, a narrative synthesis was performed. RESULTS: We included five studies involving 1849 participants (343 LTOT users) in this review. LTOT use was generally associated with a lower prevalence of cognitive impairment (18%-45%) and higher global cognitive scores, particularly in executive functions. MoCA-based assessments also consistently favored LTOT users, particularly in rural populations. However, findings were heterogeneous across studies. CONCLUSION: LTOT is associated with better cognitive performance in hypoxemic COPD patients. Prospective longitudinal studies are needed to establish causality between LTOT use and reduction in cognitive impairment in COPD.