Risk factors of incident lung diseases and the impact of DMARDs in rheumatoid arthritis patients: a longitudinal study

Objective We aimed to investigate the impact of clinical characteristics and therapy on rheumatoid arthritis (RA)-related lung diseases. Methods The retrospective cohort consisted of 1,207 inpatients at baseline. RA-related lung diseases included interstitial lung disease (ILD), bronchiectasis, pleural effusion, or pulmonary arterial hypertension. Kaplan-Meier method was used to measure the cumulative incidence curve. Cox regression was conducted to evaluate the associations between RA-related lung diseases and risk indicators. Logistic regression was employed to examine the impact of drugs. Results 145 patients developed RA-related lung diseases during a mean follow-up period of 3.5 years. The incidence of RA-related lung diseases increased, especially after 10 years of RA onset, or from the age of 55. RA-related lung diseases was independently associated with older age at RA onset (per 10 years, hazard ratio [HR] = 1.22, 95% confidence interval [CI] = 1.04–1.42), longer RA duration (per 10 years, HR = 1.43, 95%CI = 1.15–1.77), higher Rheumatic Disease Comorbidity Index (HR = 1.22, 95%CI = 1.08–1.39), history of lung infections (HR = 2.26, 95%CI = 1.58–3.24), concomitant systemic lupus erythematosus (HR = 2.36, 95%CI = 1.35–4.13). After adjustment, ever-use of methotrexate was negatively associated with RA-related lung diseases (odds ratio [OR] = 0.64, 95%CI = 0.44–0.92) and ILD (OR = 0.54, 95%CI = 0.35–0.83). Biologic or targeted synthetic disease modifying antirheumatic drugs (b/tsDMARDs) were also found protective (OR = 0.59, 95%CI = 0.35–0.99). Conclusion Our study indicated that several risk factors were associated with RA-related lung diseases, and methotrexate and b/tsDMARDs brought protective effects.