BACKGROUND AND AIM: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disorder of unknown origin, affecting approximately 3 million individuals globally. Its incidence is increasing, and the median survival following diagnosis is around 3 years. The aim of this study is to investigate the relationship between Krebs von den Lungen-6 (KL-6), Surfactant Protein A (SP-A), Surfactant Protein D (SP-D), Matrix Metalloproteinase-7 (MMP-7), Vascular Endothelial Growth Factor (VEGF), Periostin and pro-BNP levels and prognosis of IPF and to evaluate these markers according to the gender-age-physiology (GAP) index.

METHODS: Forty-seven patients diagnosed with IPF between March 2020 and January 2022 in Eskisehir Osmangazi University Faculty of Medicine Chest Diseases Clinic were included in the study. The patients were followed up closely (by performing radiological and pulmonary function tests every six months). Serum samples were analysed for KL-6, SP-A, SP-D, MMP-7, VEGF and Periostin levels.

RESULTS: The mean age of patients was 68±7 years. Twelve of these patients died during study period. None of the biomarkers showed a significant association with survival in univariate Cox regression analyses. However, GAP stage 3 was associated with markedly increased mortality compared to stage 1 (HR = 7.25, p=0.017). Biomarker levels did not differ significantly between GAP stage groups, except for pro-BNP, which was higher in stage 3 compared to stage 1 (p=0.021).

CONCLUSION: Our results show that serum KL-6, SP-A, SP-D, MMP-7, VEGF, and periostin levels were not predictive of survival in IPF, while pro-BNP levels differed across GAP stages and GAP stage 3 was strongly associated with mortality; although we did not find these biomarkers to be predictive of survival, multicenter studies with larger patient cohorts may provide further insights.