Assessment of cognition and associated factors in patients with stable chronic obstructive pulmonary disease

Abstract

To explore and analyze the cognitive function in patients with stable chronic obstructive pulmonary disease (COPD). The cognition differences between patients with COPD and healthy subjects were analyzed by Montreal Cognitive Assessment (MoCA). GOLD grade, PaO₂, PaCO₂, the education degree and the age were included as associated factors. The correlation between those factors with cognition were analyzed. The MoCA in patients with COPD was 20.6 ± 2.3, and that in healthy subjects was 25.3 ± 1.7; the difference between the 2 groups being significant (P < 0.01). The MoCA was 22.4 ± 0.8 in patients with GOLD grade I disease, 21.7 ± 1.0 in grade II, 20.2 ± 1.2 in grade III, and 19.1 ± 1.20 in grade IV diseases; the difference among the 4 subgroups being significant (F = 31.69, P < 0.05). The MoCA in GOLD grade I was higher than that in GOLD grade II, but the difference did not reach significance (P > 0.05). The MoCA of GOLD grade II was higher than that in GOLD grade III (P < 0.05) , and the MoCA of GOLD grade III was higher than that GOLD grade IV (P < 0.05). The MoCA in non-hypoxemia subgroup and hypoxemia subgroup was 22.2 ± 1.1 and 19.8 ± 1.1, respectively (P < 0.05) , while the MoCA in hypercapnia subgroup and non-hypercapnia subgroup was 20.0 ± 1.3 and 22.3 ± 1.0 respectively (P < 0.05). By regression analysis, the score of MoCA was correlated positively to education degree (Standard B1 = 0.134, P < 0.01), GOLD grade(Standard B2 = 0.351, P < 0.01) and PaO₂(Standard B3 = 0.305, P < 0.01), while the score of MoCA was correlated negatively to age(Standard B4 = -0.146, P < 0.01) and PaCO₂(Standard B5 = -0.145, P < 0.01). The MoCA score in patients with COPD was lower than that in healthy people. Lower MoCA score was found in patients with severe COPD. The MoCA scores in both hypoxemia subgroup and hypercapnia subgroup were lower. The cognitive dysfunction in patients with stable COPD was positively correlated with education degree, GOLD grade, and PaO₂, but negatively with age and PaCO₂.