# Potential Utility of Combined Presepsin and LDH Tracking for Predicting Therapeutic Efficacy of Steroid Pulse Therapy in Acute Exacerbation of Interstitial Lung Diseases: A Pilot Study

## TL;DR

This pilot study suggests that tracking presepsin and LDH levels can help predict how well steroid therapy works in patients with acute interstitial lung disease.

## Contribution

The study introduces a new combined presepsin–LDH index as a potential prognostic tool for steroid pulse therapy in AE-ILDs.

## Key findings

- High presepsin levels were observed in 13 out of 16 patients before therapy.
- The post-/pre-presepsin–LDH index showed strong discrimination for predicting poor outcomes (AUC: 0.873).
- A positive correlation was found between the post-/pre-presepsin and post-/pre-LDH ratios.

## Abstract

Background/Objectives: The usefulness of presepsin, which is released from macrophages, in acute exacerbation of interstitial lung diseases (AE-ILDs) is unknown. We aimed to investigate the utility of monitoring presepsin with other AE-ILD markers before and after steroid pulse therapy in AE-ILDs. Methods: This pilot single-center retrospective observational study involved 16 patients with AE-ILDs, including the AE of idiopathic pulmonary fibrosis and idiopathic nonspecific interstitial pneumonia and rapidly progressive connective tissue disease-associated ILD. Patients who survived 90 days were assigned to the survival group (n = 9). The remaining patients were classified in the non-survivor group (n = 7). To evaluate the therapeutic efficacy of steroid pulse therapy, specific serum markers were selected—presepsin, as a novel AE-ILD marker, and surfactant protein D, C-reactive protein, and lactate dehydrogenase (LDH), as classical AE-ILD markers. Results: Thirteen out of sixteen patients with AE-ILDs showed high presepsin levels (presepsin ≥ 470 pg/mL) before steroid pulse therapy. The post-/pre-presepsin ratio and the post-/pre-LDH ratio, calculated by dividing the presepsin and LDH levels after therapy by the levels before therapy, respectively, showed a positive correlation (r = 0.579, p = 0.021). As a result of this correlation, the post-/pre-presepsin–LDH index was created, obtained from the “post-/pre-presepsin ratio” multiplied by the “post-/pre-LDH ratio”. In a receiver operating characteristic curve analysis for non-survival, the post-/pre-presepsin–LDH index showed good discrimination as a prognostic marker for a poor outcome (AUC: 0.873, 95% confidence interval: 0.655–0.999). Conclusions: Tracking presepsin and LDH simultaneously may be useful for determining treatment response to steroid pulse therapy in the clinical management of AE-ILDs.