Risk factors of Pulmonary Manifestations in Systemic Lupus Erythematosus: insights from a large retrospective cohort

Introduction - Pulmonary manifestations in systemic lupus erythematosus (SLE) are rare but potentially severe. This study aimed to describe the characteristics of SLE patients with lung involvement and identify predictive factors for pulmonary manifestations in a large cohort. Methods - We conducted a retrospective observational analysis of 924 SLE patients from the LESLY cohort in Lyon, France. Patients were diagnosed using EULAR/ACR 2019 criteria. We performed univariate and multivariate survival analyses to identify risk factors for pulmonary involvement. Results - Of 924 SLE patients, 29 (3.1%) developed respiratory involvement beyond pleuritis. Interstitial lung disease was the most common manifestation (65.5%). Significant risk factors for pulmonary involvement included older age at diagnosis (≥40 years; HR 2.26, 95% CI 1.04-4.93), higher BMI (≥25 kg/m²; HR 3.21, 95% CI 1.52-6.79), and presence of anti-RNP antibodies (HR 2.30, 95% CI 1.09-4.85). Hydroxychloroquine use showed a strong protective effect (HR 0.11, 95% CI 0.05-0.23). The mortality rate was 7.1%, exclusively in the ILD subgroup. Conclusion - Our study identifies key risk factors for pulmonary manifestations in SLE and highlights the protective role of hydroxychloroquine. These findings may inform risk stratification and management strategies for SLE patients at risk of respiratory complications.