Table S1.

Comparison of each PHQ-9 item in patients with COPD and non-COPD^a

PHQ-9 items	Non-COPD (N=2,224)	COPD (N=211)	P-value
PHQ1 (little interest or pleasure in doing things)	0.30±0.70	0.24±0.64	0.21
PHQ2 (feeling down, depressed, or hopeless)	0.26±0.62	0.16±0.47	0.02
PHQ3 (trouble falling or staying asleep, or sleeping too much)	0.53±0.90	0.43±0.84	0.10
PHQ4 (feeling tired or having little energy)	0.63±0.91	0.49±0.85	0.04
PHQ5 (poor appetite or overeating)	0.26±0.65	0.19±0.60	0.18
PHQ6 (feeling bad about yourself, or that you are a failure or have let yourself or your family down)	0.18±0.54	0.21±0.60	0.54
PHQ7 (trouble concentrating on things, such as reading the newspaper or watching television)	0.12±0.47	0.12±0.46	0.98
PHQ8 (moving or speaking so slowly that other people could have noticed, or the opposite, being so fidgety or restless that you have been moving around a lot more than usual)	0.08±0.38	0.06±0.30	0.44
PHQ9 (thoughts that you would be better off dead or hurting yourself in some way)	0.10±0.41	0.06±0.31	0.21
Total score	2.46±3.50	1.95±3.07	0.04

Note:

^aData are presented as mean ± SD.

Abbreviation: PHQ-9, Patient Health Questionnaire-9.