TABLE 3.

LOGISTIC REGRESSION MODELS WITH PREDICTORS OF SEVERE ASTHMA (SEVERE VS. NOT SEVERE) AMONG SUBJECTS WITH ASTHMA ONLY

	Model 1 (n = 62)		Model 2 (n = 107)		Model 3 (n = 98)
Predictor	Odds Ratio	Adjusted P Value	Odds Ratio	Adjusted P Value	Odds Ratio	Adjusted P Value
Baseline FEV1% predicted	1.00 (0.96, 1.04)	0.92	0.98 (0.95, 1.01)	0.20	0.98 (0.94, 1.02)	0.26
Maximum reversibility	1.04 (0.99, 1.08)	0.093	1.03 (1.00, 1.07)	0.076	1.05 (1.00, 1.09)	0.0372
BALF PGD2*	3.11 (1.17, 8.26)	0.023	1.78 (0.90, 3.54)	0.097	1.37 (0.53, 3.53)	0.51
Age, yr	1.07 (1.01, 1.14)	0.031	1.08 (1.03, 1.14)	0.0032	1.10 (1.03, 1.17)	0.0039
MCTC/MCTot*	6.16 (1.35, 28.25)	0.019	3.00 (0.82, 11.00)	0.095	5.08 (1.06, 24.24)	0.0418
African American (ref: white)	2.76 (0.71, 10.68)	0.14	2.52 (0.81, 7.85)	0.11	3.66 (0.62, 21.68)	0.145
Clinical center
Overall P value					—–	0.0263
CLC					0.40 (0.03, 4.75)
WFU					0.19 (0.02, 2.09)
WIS					0.19 (0.02, 2.09)
WSL					0.23 (0.01, 3.87)
PITT (reference)					1.00

Definition of abbreviations: BALF = bronchoalveolar lavage fluid; CLC = Cleveland Clinic, Cleveland, OH; MC_TC = both tryptase- and chymase-positive mast cells; MC_Tot = total mast cells; PDG2 = prostaglandin D2; PITT = National Jewish Health, Denver, CO, and University of Pittsburgh, Pittsburgh, PA; WIS = University of Wisconsin, Madison, WI; WFU = Wake Forest University, Winston-Salem, NC; WSL = Washington University, St. Louis, MO.

Model 1: all listed predictors of severe vs. not severe asthma included. Model 2: multiple imputation model with data imputed for the missing MC_TC. Model 3: multiple imputation model controlling for clinical center; excludes University of Virginia and Brigham and Women's Hospital due to too few cases.

^*Log transformation was applied to BALF PGD2 and square root transformation was applied to MC_TC/MC_Tot for modeling purposes.