Plasma SH Concentrations and Mortality in Patients with Newly Diagnosed Idiopathic Pulmonary Fibrosis.

INTRODUCTION: Oxidative stress plays a critical role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), yet its prognostic significance remains unclear. This study investigated the association between plasma sulfhydryl (SH) group concentrations and thiobarbituric acid reactive substances (TBARS), systemic markers of oxidative stress, and mortality in patients with IPF. MATERIALS AND METHODS: Eighty-eight patients with newly diagnosed IPF were recruited between 2016 and 2023 for the purposes of the study. Plasma SH and TBARS were measured at baseline under standardized conditions and normalized to plasma protein content. Survival analyses were performed using Kaplan-Meier curves and Cox regression models, adjusting for lung function parameters and IPF stage. RESULTS: Patients with lower SH concentrations had significantly higher mortality (log-rank p = 0.012). SH group concentrations, but not TBARS, were independently and negatively associated with survival in multivariate models adjusting for %TLC, %FVC, %DLCO, and IPF stage (HR: 0.606, 95% CI: 0.443-0.830, p = 0.0018). CONCLUSIONS: Low plasma SH concentrations, reflecting systemic redox imbalance, are independently associated with increased mortality in newly diagnosed IPF. SH quantification represents a promising prognostic biomarker in IPF.