Matrix metalloproteinase-9 predicts pulmonary status declines in α1-antitrypsin deficiency

Respiratory Research

Table 2 Baseline cross-sectional association of plasma MMP-9 with pulmonary status among 126 alpha₁-antitrypsin deficient subjects with emphysema

	Δ (95% CI)*	P-value
Spirometry
FEV₁, ml	-32 (-61 to -4)	0.03
FVC, ml	-105 (-160 to -52)	<0.001
FEV₁/FVC ratio	+0.2% (-0.3% to +0.7%)	0.47
Total Lung Capacity, ml	-64 (-154 to +26)	0.16
Transfer Factor (TLco), mmol/min/kpa	-0.1 (-0.2 to -0.01)	0.03
CT densitometry
Adjusted Lung Density^†	-0.24 (-1.1 to +0.6)	0.58
Resting O₂ saturation (room air)	-0.2% (-0.3% to -0.03%)	0.02
Incremental Shuttle Walk Test
Distance Walked, meters	-12 (-22 to -2)	0.02

All analyses controlled for age, gender, race-ethnicity, leukocyte count, and tobacco pack-year history. Analysis of total lung capacity also controlled for method of lung capacity assessment (box plethysmography vs helium dilution).
*Change (Δ) associated cross-sectionally with a 25^th - 75^th percentile interquartile range higher level of MMP-9.
^†Measured in Hounsfield Units at the 15^th percentile.

ISSN: 1465-993X