This study investigated whether specific sulfatase modifying factor-1 (SUMF1) SNPs—previously linked to lung function—are associated with COPD progression and response to inhaled corticosteroid (ICS) treatment, specifically budesonide, given that SUMF1 expression is altered in COPD and its variants linked to increased disease risk. This evidence concerns the gene SUMF1 and chronic obstructive pulmonary disease.