Correlation between frailty and reduced cortical thickness in Chronic Obstructive Pulmonary Disease.

Introduction: Physical inactivity and cognitive impairment in patients with chronic obstructive pulmonary disease (COPD) leads to frailty which is associated with poor prognosis. However, little is known on the impact of the pathophysiology on the human brain. Aims and objectives: We hypothesized that brain structure could change according to frailty in COPD. We aimed to clarify the relationship between frailty and cortical thickness. Methods: Cortical thickness measured MRI and the frailty score assessed using the Kihon Checklist (KCL) which is a self-reporting questionnaire were assessed in 40 stable COPD patients and 20 healthy controls. Results: In 34 cortical regions on each side, 12 on the right and 13 on the left were found to be significantly thinner in the COPD than in the healthy (p＜0.05, respectively). We examined the association between these regions and frailty score. We found 7 regions with significant negative correlations in COPD, but no in the healthy. Even when adjusted by age, one region on the left and 5 regions on the right showed significant correlations. The correlation coefficient between the bilateral superior frontal gyrus and frailty score were the largest (left: ρ = -0.5308, right: ρ = -0.5361) (p＜0.05). Interestingly, among the KCL, question domain including daily activities showed strongest correlation, with a sensitivity of 90% and a specificity of 73% to capture bottom quartile of thinning of the superior frontal gyrus if 2 of the 5 questions were applicable (left: AUC=0.85, right: AUC=0.88). Conclusion: Frailty in COPD is associated with decreased thickness of specific brain cortical regions, and most pronounced in the superior frontal gyrus. Moreover, KCL could be a useful tool to capture brain frailty.