Based on these findings, we next performed logistic regression analyses adjusted for multiple covariates (age, sex, body mass index, asthma duration, ACQ score, post-bronchodilator FEV1 [% of predicted], and IS IL-8 levels categorized as <3.096 pg/mL vs. ≥3.096 pg/mL, using the overall median as the cutoff) to identify independent risk factors for the COPD-A etiotype (Table 6). This evidence concerns the gene CXCL8 and chronic obstructive pulmonary disease.