Fig. 1From: Serum IgG subclass levels and risk of exacerbations and hospitalizations in patients with COPDComparison of rates of COPD exacerbations in person-years between participants with IgG subclass deficiency and normal IgG subclass levels in the merged dataset (MACRO and STATCOPE cohorts combined, n = 1629). Error bars represent 95% confidence intervalBack to article page