Table 4.

Cross-validated partial least squares discriminant analysis prediction of the n6MWD variation classes over the year of followup based only on BIONOTE (top), only on GOLD classification (center) and on BIONOTE + GOLD classification (bottom)

BIONOTE-based prediction of Δn6MWD classes	Reference Δn6MWD classes
	Worsened	Stable/improved
Worsened	28	5
Stable/improved	4	26
Accuracy: 0.86 (95% CI 0.75–0.93, P < 0.001). Sensitivity: 0.84; specificity: 0.88. Cohen’s kappa: 0.71 (95% CI 0.54–0.88, P < 0.001)
GOLD-based prediction of Δn6MWD classes	Reference Δn6MWD classes
	Worsened	Stable/improved
Worsened	15	13
Stable/improved	17	18
Accuracy: 0.52 (95% CI 0.39–0.65, P = 0.45). Sensitivity: 0.58; specificity: 0.47. Cohen’s kappa: 0.05 (95% CI –0.20 to 0.29, P = 0.35)
BIONOTE + GOLD-based prediction of Δn6MWD classes	Reference Δn6MWD classes
	Worsened	Stable/improved
Worsened	25	6
Stable/improved	7	25
Accuracy: 0.79 (95% CI 0.67–0.88, P < 0.001). Sensitivity: 0.81; specificity: 0.78. Cohen’s kappa: 0.59 (95% CI 0.39 to 0.79, P < 0.001)

Abbreviations: n6MWD, 6-minute walking test distance normalized by squared height; GOLD, Global Initiative for Chronic Obstructive Lung Disease.