Table 3

Unadjusted OR and 95% CI of crackles for COPD by crackle characteristics

	Observer 1			Observer 2
	n	OR (95% CI)	P value	n	OR (95% CI)	P value
No certain crackles	3296	1 (reference)		3223	1 (reference)
Coarse versus fine
Fine inspiratory crackles one lung base, no inspiratory crackles on the other	36	1.10 (0.26 to 4.63)	0.9	116	0.84 (0.34 to 2.07)	0.7
Fine inspiratory crackles both lung bases	9	2.34 (0.29 to 18.84)	0.4	17	2.47 (0.56 to 10.90)	0.2
Coarse crackles one lung base2	196	2.25 (1.39 to 3.63)	0.001	149	2.39 (1.41 to 4.05)	0.001
Coarse inspiratory crackles both bases	65	3.01 (1.46 to 6.19)	0.003	38	4.19 (1.82 to 9.65)	0.001
Early* versus late
Late inspiratory crackles at one lung base, no inspiratory crackles on the other	155	1.16 (0.58 to 2.31)	0.7	130	0.44 (0.14 to 1.39)	0.2
Late inspiratory crackles at both lung bases	37	1.07 (0.26 to 4.49)	0.9	17	0	1.0
Early inspiratory crackles at one lung base	94	3.84 (2.20 to 6.73)	<0.001	139	2.41 (1.40 to 4.15)	0.002
Early inspiratory crackles at both lung bases	20	8.03 (3.05 to 21.16)	<0.001	37	8.90 (4.39 to 18.02)	<0.001
Both early and coarse
Early and coarse inspiratory crackles at one lung base	84	4.75 (2.73 to 8.28)	<0.001	102	3.45 (1.98 to 6.01)	<0.001
Early and coarse inspiratory crackles at both lung bases	13	5.62 (1.53 to 20.62)	0.009	18	9.27 (3.44 to 25.00)	<0.001
Other certain crackles	291	1.16 (0.70 to 1.94)	0.6	341	0.97 (0.58 to 1.62)	0.97

*'Early crackles’ and ‘both early and late crackles’ are included in the category ‘early’.
COPD, chronic obstructive pulmonary disease.