Seropositive non-CTD ILD not linked to improved outcomes, treatment response

Seropositivity in patients with interstitial lung disease (ILD) without connective tissue disease (CTD) does not seem to contribute to improved outcomes or treatment response, a study has shown.

This finding suggests the importance of other disease features in determining prognosis and predicting response to immunosuppression, according to the investigators.

A prospective registry was used to identify a total of 1,570 non-CTD patients (with idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, interstitial pneumonia with autoimmune features, or unclassified ILD) and 181 rheumatoid arthritis (RA)-ILD patients.

The investigators used linear mixed-effect and Cox proportional hazards models, adjusted for age, sex, smoking pack-years, and baseline forced vital capacity (FVC), to compare longitudinal FVC, transplant-free survival, and incidence of progressive fibrosing-ILD (PF-ILD) between seronegative non-CTD ILD (reference group), seropositive non-CTD ILD, and RA-ILD.

They also analysed the interaction between seropositivity and immunosuppression on FVC decline in patients with at least 6 months of follow-up before and after treatment.

Of the patients, 217 (13.8 percent) had seropositive non-CTD ILD who showed similar rates of FVC decline and transplant-free survival compared to those with seronegative non-CTD ILD. However, they were more likely to meet the criteria for PF-ILD (hazard ratio [HR], 1.35; p=0.004).

RA-ILD patients had slower FVC decline (p=0.03), less PF-ILD (HR, 0.75; p=0.03), and lower likelihood of lung transplant or death (HR, 0.66; p=0.01) than those with seronegative non-CTD ILD. Of note, no interaction was observed between seropositivity and treatment on FVC decline in non-CTD ILD.