The Synergistic Role of Osteopontin and α-1-antitrypsin in Plasma in the Diagnosis of Unexplained COPD

Background: Osteopontin, a pleiotropic glycoprotein with roles in inflammation and tissue remodelling, and α‑1‑antitrypsin, an important anti-protease and acute phase reactant protein are novel biomarkers in respiratory disease. Their possible value in the evaluation of unexplained chronic obstructive pulmonary disease (COPD) is yet to be investigated. Materials and Methods: This case–control study consisted of 68 patients with idiopathic COPD and 77 age- and sex-matched controls who were healthy, conducted at Al-Shaab Hospital, Baghdad, Iraq between March 2024 and February 2025. The levels of serum osteopontin and α‑1‑antitrypsin were determined by enzyme linked immunosorbent assay (ELISA). Baseline demographic and clinical data were collected, and differences, correlations, and diagnostic performance were evaluated. Results: As compared to the controls, patients in whom COPD could not be established revealed significantly increased mean serum osteopontin (86.4 ± 18.7 pg/mL) levels as compared to control subjects (61.2 ± 14.9 pg/ mL, P