Determinants of fungal infection and hospital readmission risk in interstitial pneumonia with autoimmune features: associations with vitamin D and pirfenidone.

BACKGROUND

Fungal infections significantly compromise the prognosis of patients with interstitial pneumonia with autoimmune features (IPAF). However, the specific immune-related risk factors and their impact on clinical stability remain poorly defined. This study aimed to identify independent predictors for fungal infection and early readmission to optimize risk stratification.

METHODS

We conducted a retrospective analysis of 98 patients meeting the 2015 European Respiratory Society/American Thoracic Society (ERS/ATS) IPAF classification criteria. Fungal infections were confirmed through clinical manifestations, radiological findings, and metagenomic next-generation sequencing (mNGS). Logistic and Cox regression models were employed to identify factors independently associated with fungal infection and hospital readmission.

RESULTS

Fungal infection was identified in 40.8% of the cohort, with Candida albicans as the primary pathogen. Respiratory failure (odds ratio [OR]=3.76, 95% confidence interval [CI]: 1.24-11.38) and hypertension (OR = 2.94, 95% CI: 1.01-8.64) were independent associated with higher risks of fungal infection. Vitamin D (OR = 0.94, 95% CI: 0.89-0.99) and pirfenidone (OR = 0.17, 95% CI: 0.04-0.71) were independently associated with lower risks of fungal infection. Regarding prognosis, anti-Ro-52 (hazard ratio [HR]=2.23, 95% CI: 1.06-4.68) and anti-PL-12 (HR = 3.87, 95% CI: 1.11-13.44) antibody positivity independently predicted 3-month and 6-month hospital readmission, respectively.

CONCLUSION

Fungal infections in IPAF involve a complex interplay between clinical comorbidities and immune status. In this single-center retrospective cohort, vitamin D and pirfenidone were independently associated with lower risks of fungal infection and hospital readmission after adjustment for confounders. These findings should be interpreted as associations rather than evidence of causality and require validation through large-scale, multicenter prospective studies.