Objective: Periostin is a matricellular protein that has been associated with type 2-driven airway inflammation and asthma pathobiology. This study aimed to evaluate serum periostin levels in Iraqi adults with asthma compared with healthy controls, and additionally it examined the associations with disease severity and the Global Initiative for Asthma defined control status. Furthermore, the study assessed the diagnostic performance using the Receiver Operating Characteristic curve analysis for discriminating asthma cases.
Materials and Methods: A comparative cross-sectional study was conducted at Al-Imamain Al-Kadhimain Medical City and in the laboratories of the Department of Chemistry and Biochemistry at the College of Medicine, University of Al-Nahrain in Baghdad, Iraq. A total of 90 asthmatic patients and 90 healthy controls matched for age, sex, body mass index, and socioeconomic status were registered between April 2025 and January 2026. Serum periostin levels were measured using an Enzyme-linked immunosorbent assay (ELISA) and analyzed using nonparametric statistics.
Results: Periostin levels were significantly higher in asthmatics compared to controls, median 51.8 ng/ml (IQR: 44.9 - 57.9) vs. 32.9 ng/ml (IQR: 26.8 - 40.1), p <0.001. Periostin increased significantly with disease severity (p < 0.001) and asthma control worsening (p=0.006), peaking at uncontrolled severe disease. Eosinophilic patients had higher periostin levels in comparison to the non-eosinophilic phenotypes, median 52.96 ng/mL (IQR: 47.9 - 59.5) vs 47.64 ng/mL (IQR: 41.9 - 52.8); p=0.003. Receiver Operating Characteristic curve calculation yielded an area under the curve value of 0.904, and a 95% Confidence interval 0.851 to 0.943, achieving 92.2% sensitivity and 73.3% specificity at a >38.5 cut-off.
Conclusion: These findings show that periostin is associated with inflammatory status and significantly associated with poor asthma control and increased disease severity in adult Iraqi asthmatics, supporting its utility as a clinically applicable biomarker for T2-high asthma phenotyping and disease monitoring