Correlation between frailty and reduction in cortical thickness in patients with chronic obstructive pulmonary disease

Abstract

Physical inactivity and cognitive impairment in patients with chronic obstructive pulmonary disease (COPD) can lead to frailty and poor prognoses. However, little is known regarding the association between frailty and the human brain. We hypothesized that the brain structure could change according to frailty in patients with COPD and focused on cortical thickness. Cortical thickness measured by magnetic resonance imaging and frailty scores using the Kihon Checklist (KCL) were assessed in 40 patients with stable COPD and 20 healthy controls. Among the 34 regions assessed, multiple regions were thinner in patients with COPD than in healthy individuals (p < 0.05). We found significant negative correlations between the eight regions and the KCL scores only in patients with COPD. After adjusting for age and cognitive impairment, the association between the left and six right regions remained statistically significant. The correlation coefficient was the strongest in the bilateral superior frontal gyrus (left: ρ = - 0.5319, p = 0.0006) (right: ρ = - 0.5361, p = 0.0005). Interestingly, among the KCL scores, the daily activity domain showed the strongest correlation (sensitivity, 90%; specificity, 73%) with the bottom quartile of the reduction in the superior frontal gyrus. Frailty in patients with COPD is associated with a thickness reduction in the cortical regions, reflecting social vulnerability.

Figure 1

Frailty specific cortical thickness reduction area in patients with COPD. In the partial correlation between frailty and cortical thickness with age as a covariate, areas specific to patients with COPD are shown in this figure. Each cortical area is highlighted in a different color. (a) left and (b) right hemispheres.

Figure 2

Frailty and cortical thickness reduction in the superior frontal gyrus. A scattergram of the association between the KCL score and cortical thickness of the superior frontal gyrus. (a) left side in the healthy, (b) left side in COPD, (c) right side in the healthy, (d) right side in COPD.

Figure 3

Utility of daily activity domain to capture cortical thickness reduction. Receiver operating characteristic (ROC) curves were plotted to evaluate the usefulness of KCL1-5 scores in detecting cortical thickness reduction in the superior frontal gyrus. (a) left and (b) right.