Predictive factors for progressive fibrosing interstitial lung disease in anti-synthetase syndrome

Interstitial lung disease (ILD) is common in anti-synthetase syndrome (ASS). Progressive fibrosing ILD (PF-ILD) may develop in ILD with autoimmune features. Data on PF-ILDs in ASS as a group are scarce. This study aimed to explore the characteristics and predictors of PF-ILD in ASS patients.

This retrospective study enrolled 96 ASS-ILD patients. Baseline clinical data were collected. PF-ILD assessments were conducted at every hospital visit during windows of 24 months after initial diagnosis. Phenotypic, survival features and predictors of PF-ILD were estimated through SPSS 22.0.

The results revealed that 35.42% (34/96) were evaluated to be PF-ILD with a median interval time of 14.73 months. Nonspecific interstitial pneumonia was the most common radiological pattern of PF-ILD. Ground glass opacity (GGO), traction bronchiectasis and reticulation were representative high-resolution computed tomography findings of this group. Compared with the non-progressive group, PF-ILD patients had higher frequencies of anti-Ro-52 antibodies (91.18% vs 66.13%, P = 0.007) and GGO in the lower + middle and lower + middle + upper zones of the left lung, as well as lower + middle zones in the right lung (85.30% vs 54.84%, P = 0.003; 64.71% vs 38.71%, P = 0.015; 82.35% vs 58.06%, P = 0.016). Multivariate Cox analysis identified that anti-Ro-52 antibody (hazards ratio [HR] 3.55, 95% CI 1.06-11.90, P = 0.040) and GGO in left lower + middle lung zones (HR 22.11, 95% CI 1.95-250.90, P = 0.012) were independent risk factors for PF-ILD.

PF-ILD was associated with poor prognosis. Over one-third of ASS-ILD patients may develop to PF-ILD. Anti-Ro-52 antibody positivity and GGO in left lower + middle lung zones were independent risk factors for PF-ILD in ASS patients.