Table 2. Protein analyte differences between COPD and control disease severity groups.

Analyte	Non-Smokers (N  = 30)	Smokers (N  = 15)	GOLD I/II (N  = 75)	GOLD III/IV (N  = 65)	P (FDR)
EN-RAGE	13.1 (7.7 − 17.4)	20.0 (13.0 − 27.6)	19.5 (12.5 − 29.2)	35.5 (20.0 − 53.5)	0.001
TGF−α*	0.051 (0.045 − 0.055)	0.068 (0.053 − 0.075)	0.048 (0.042 − 0.060)	0.058 (0.045 − 0.073)	0.003
sRAGE	4.2 (3.3 − 5.2)	3.2 (2.4 − 5.0)	2.7 (1.5 − 3.5)	2.2 (1.5 − 3.0)	0.003
Fibrinogen	0.37 (0.34 − 0.42)	0.46 (0.44 − 0.49)	0.43 (0.37 − 0.47)	0.46 (0.42 − 0.53)	0.004
NGAL*	309.2 (258.6 − 354.2)	273.7 (233.2 − 338.1)	269.0 (211.0 − 340.2)	351.5 (272.5 − 441.5)	0.005
MPO*	414.5 (352.5 − 457.9)	382.0 (284.0 − 622.0)	379.0 (268.0 − 581.2)	553.0 (345.0 − 806.0)	0.02
HB-EGF*	0.18 (0.15 − 0.24)	0.23 (0.17 − 0.27)	0.18 (0.12 − 0.24)	0.27 (0.17 − 0.32)	0.02

Data are expressed as median (interquartile range) in ng/ml for individual analytes, except for Fibrinogen which is in mg/dl.

All analyte data shown are from profiling on the RBM Luminex platform, except for Fibrinogen which was tested at Hospital Grosshansdorf. COPD subjects were grouped as GOLD I/II (mild/moderate) and GOLD III/IV (severe/very severe). ANOVA was used for group-wise comparisons, except for analytes noted with *, which did not follow a normal distribution and a non-parametric Kruskal Wallis test was used.