Association between the Lung Immune Prognostic Index and mortality in patients with idiopathic inflammatory myopathy-associated interstitial lung disease

Objective: To explore the association between the Lung Immune Prognostic Index (LIPI) and 1-year all-cause mortality in patients with idiopathic inflammatory myopathy related interstitial lung disease (IIM-ILD). Methods: Patients who were diagnosed with IIM-ILD at West China Hospital, Sichuan University from January 2008 to December 2021 were retrospectively included and categorized into three groups based on LIPI. Univariable and multivariable Cox proportional hazards models were conducted to explore potential association between the LIPI and patients' mortality. Results: A total of 1116 patients were screened, and 830 were included in this study. The multivariable Cox analysis showed that, compared with patients with poor LIPI, the hazard ratio (HR) for all-cause 1-year mortality was 0.22 (95% CI 0.05-0.93, P=0.04) for patients in the good LIPI group (LDH<250 IU/L and dNLR<3). After excluding patients lost to follow-up within one year, a similar result was found for LIPI (HR 0.20, 95% CI 0.05-0.86; P=0.03). Conclusions: Good LIPI was independently associated with decreased risk of all-cause 1-year mortality in patients with IIM-ILD. This easy-to-obtain index might be served as a potential marker for assessing the prognosis of IIM-ILD.