Table 3.
Unadjusted and adjusted hazard ratios for COPD exacerbations according to IgG subclass levels in the MACRO and STATCOPE cohorts
| MACRO – Time to first Exacerbation | ||||
| IgGa | Univariate analysis | Multivariate analysisb | ||
| Hazard Ratio (95% CI) | P | Hazard Ratio (95% CI) | P | |
| IgG1 | 1.43 (1.23–1.67) | < 0.001 | 1.30 (1.10–1.54) | 0.002 |
| IgG2 | 1.29 (1.15–1.45) | < 0.001 | 1.19 (1.05–1.35) | 0.006 |
| IgG3 | 0.99 (0.88–1.11) | 0.84 | 0.95 (0.85–1.07) | 0.39 |
| IgG4 | 1.09 (1.02–1.17) | 0.009 | 1.05 (0.98–1.13) | 0.17 |
| STATCOPE – Time to first Exacerbation | ||||
| IgGa | Hazard Ratio (95% CI) | P | Hazard Ratio (95% CI) | P |
| IgG1 | 1.45 (1.20–1.75) | < 0.001 | 1.25 (1.02–1.54) | 0.035 |
| IgG2 | 1.32 (1.15–1.52) | < 0.001 | 1.17 (1.01–1.36) | 0.046 |
| IgG3 | 1.10 (0.98–1.25) | 0.11 | 0.99 (0.87–1.13) | 0.90 |
| IgG4 | 1.01 (0.94–1.08) | 0.76 | 0.96 (0.89–1.04) | 0.33 |
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