Association between IgE levels and asthma severity among African American, Mexican, and Puerto Rican patients with asthma

Background: High levels of IgE are associated with asthma. Whether higher levels of IgE are associated with more severe asthma is still unclear. Objective: To determine whether IgE is associated with asthma severity among Latino and African American subjects with asthma. Methods: We assessed lung function and asthma severity among African American, Mexican, and Puerto Rican patients with asthma with high IgE levels (>= 100 IU/mL; n = 492) and compared these values to those of patients with asthma with low IgE levels (< 100 IU/mL; n = 247). We also examined IgE as a continuous variable among these groups. Results: Patients with asthma with high IgE had a lower mean FEV1 (87.6 +/- 17.1, percent of predicted) than patients with asthma with low IgE (91.5 +/- 17.0; P = .031). Regardless of race and ethnicity, baseline FEV1, forced expiratory How, and FEV1/ forced vital capacity were lower among subjects with high IgE than among subjects with low IgE (P = .031, P < .0001, P = .0001, respectively). In addition, 54.7% of patients with asthma with high IgE had been previously hospitalized, compared with 44.1% of patients with asthma with low IgE (odds ratio, 1.33; 95% CI, 1.04-1.71). Conclusion: Higher IgE is associated with lower baseline lung function and more severe asthma among these populations. Clinical implications: Among patients with asthma from 3 ethnically distinct groups, total IgE levels are inversely correlated with baseline lung function and asthma severity.