Serum IgG subclass levels and risk of exacerbations and hospitalizations in patients with COPD

Respiratory Research

Table 4 Unadjusted and adjusted hazard ratios related to hospitalizations according to IgG subclass levels in the MACRO and STATCOPE cohorts

MACRO – Time to first Hospitalization
IgG^a	Univariate analysis		Multivariate analysis^b
IgG^a	Hazard Ratio (95% CI)	P	Hazard Ratio (95% CI)	P
IgG1	1.51 (1.16–1.99)	0.003	1.52 (1.15–2.02)	0.004
IgG2	1.37 (1.12–1.67)	0.002	1.33 (1.08–1.64)	0.007
IgG3	1.03 (0.85–1.24)	0.79	1.01 (0.84–1.44)	0.90
IgG4	1.01 (0.89–1.12)	0.99	1.00 (0.88–1.12)	0.94
STATCOPE – Time to first Hospitalization
IgG^a	Univariate analysis		Multivariate analysis^b
IgG^a	Hazard Ratio (95% CI)	P	Hazard Ratio (95% CI)	P
IgG1	1.33 (0.98–1.80)	0.07	1.27 (0.91–1.76)	0.16
IgG2	1.39 (1.11–1.74)	0.004	1.43 (1.12–1.83)	0.004
IgG3	0.97 (0.79–1.19)	0.75	0.90 (0.73–1.12)	0.36
IgG4	1.08 (0.95–1.22)	0.22	1.06 (0.93–1.20)	0.39

^aIgG subclass levels expressed using a negative-log transformation (base 2), with one-unit increase on this log scale being equivalent to a 50% decrease of IgG subclass levels. ^bAdjusted hazard ratios for IgG levels were calculated using a Cox Proportional Hazards model with adjustments for the following covariates: study drug (azithromycin vs. placebo in MACRO - First cohort; simvastatin vs. placebo in STATCOPE - Replication cohort), age, gender, ethnicity (Caucasian vs. Non-Caucasian), FEV₁ (% of predicted values), smoking status (current vs. former smokers), oxygen dependence, inhaled corticosteroid use, and treatment with systemic steroids in previous year. Legend: 95% CI = 95% Confidence Interval

ISSN: 1465-993X