Table 2

Unadjusted OR and 95% CIs of crackles for COPD by location

	Observer 1			Observer 2
	n	OR (95% CI)	P value	n	OR (95% CI)	P value
No certain or doubtful crackles	3096	1 (reference)		3096	1 (reference)
Crackles by location
Certain inspiratory crackles at one lung base	221	1.91 (1.19 to 3.08)	0.008	246	1.44 (0.87 to 2.39)	0.2
Certain inspiratory crackles at both lung bases	85	3.00 (1.60 to 5.63)	0.001	77	3.70 (2.00 to 6.86)	<0.001
Certain crackles elsewhere*	82	0.94 (0.34 to 2.59)	0.9	138	1.12 (0.54 to 2.33)	0.8
Questionable crackles†	200	0.56 (0.25 to 1.29)	0.2	127	0.59 (0.22 to 1.63)	0.3

*Expiratory crackles are included.
†Classified as possible crackles in first round of classification, but as uncertain or no crackles in second round.
COPD, chronic obstructive pulmonary disease.