Table 4.

Receiver Operating Characteristic (ROC) Curve Analysis of the Different Tests Used to Identify COPD Patients with a Very Low Level of Physical Activity (<5000 Steps/Day)

Test	AUC	95% CI	P value	Best Cut-Off
6-minute walk distance	0.802	0.720–0.884	<0.001	350 m
4-meter gait speed	0.698	0.600–0.798	<0.001	0.8 m/s
30-second chair stand test	0.676	0.576–0.776	0.001	11 stands
Timed up and go test	0.752	0.658–0.846	<0.001	10 s
Handgrip strength	0.596	0.491–0.702	0.082	30 kg
Fat-free mass index	0.502	0.440–0.752	0.088	19 kg/m2
Calf circumference	0.601	0.496–0.707	0.066	36 cm
Arm muscle area	0.612	0.506–0.718	0.114	48 cm2
Rectus femoris cross-sectional area	0.589	0.483–0.695	0.106	6 cm2

Abbreviations: AUC, area under the curve; CI, confidence interval.