The relationship between cognitive function and arterial partial pressure O(2) in patients with COPD: A meta-analysis

BACKGROUND: The high incidence of cognition disorders in chronic obstructive pulmonary disease (COPD) patients represents a main focus in public health field recently. Thus, we tried to explore relationship between cognitive function and arterial partial pressure O(2) (PaO(2)) in patients with COPD as assessed by Mini-mental State Examination (MMSE) and/or Montreal Cognitive Assessment (MoCA). MATERIALS AND METHODS: Medical and scientific literature databases, such as Web of Science, PubMed, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Database, were searched independently by 2 reviewers until February 2016. Correlation coefficient (r or r(s)) values were obtained from each study, and 95% confidence intervals (CIs) were calculated using STATA12.0 software. RESULTS: A total of 2049 studies were produced, and 9 of which were analyzed (714 participants) in the meta-analysis. The pooled r observed medium relationship for all selected studies (r = 0.405, 95% CI 0.31–0.55), and notable heterogeneity was also tested between studies (χ(2) = 17.72, P = .023; I(2) = 54.9%). After the sensitivity and subgroup analysis, the heterogeneity significantly decreased. Subgroup analysis showed that MMSE score was stronger correlation between PaO(2) and cognitive function than MoCA score in the COPD patients. Begg test did not indicate potential risk of publication bias. CONCLUSIONS: There was a negative correlation between cognitive function and anoxia in patients with COPD, so it may be extremely essential to predict and improve the status of hypoxia in COPD patients.