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

Abstract Objectives 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. Methods 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. Results 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. Conclusions 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.