Features and functional deterioration in interstitial lung disease (ILD) asociated to rheumatoid arthritis (RA)

Purpose: To describe the characteristics of ILD-RA patients and to asess their inicence rate of functional respiratory impairment Methods: This is a longitudinal prospective study. A cohort of RA patients diagnosed of ILD since 02/2007 until 03/2018 and followed till 05/2018, in a ILD unit, carried by a pneumologist and a rheumatologist. The main variable was FVC decline ≥ 10 % pred value since the previous visit. Covariables: sociodemographic, basal comorbidities, radiological pattern (UIP, NSIP), laboratory tests, therapy (corticoids, Azathioprine [AZA], Mycophenolate [MMF], Leflunomide [LEF], anti-TNF, Abatacept [ABA], Rituximab [RTX]. Survival techniques were used to estimate the incidence rate (IR) of functional impairment, expressed per 100 patient-years [95 % CI]. Results: We included 43 patients, 63% women, mean age 70±9.6 years. 42% never smoked. HTN and vascular disease were frecuent comorbidities, RF was positive in 85% and anti-CCP in 82%, ESR was 43±26. UIP pattern in 63%, NSIP in 32 %. Median FVC were 103%. 33 patients used Corticoids, 4 MMF, 18 AZA, 16 LEF, 6 TNFs, 20 RTX and 5 ABA. 37% sufered functional deterioration, IR of 17 [11-25] (141 patients-years). 50% achieved funtional deterioration at 4.6 years since the ILD diagnosis. IR for UIP was 18 [11-30] and for NSIP 16 [8-29]. Corticoids IR was 15[10-24], LEF 13[6-29], AZA and MMF 17[8-36], RTX 11 [4-29] Conclusion: RA patients had active disease at ILD diagnosis. The most common radiological pattern was UIP. 37% of patients suffered functional deterioration with IR of 17% patient-years, being 4.5 years the median time free of impairment. The crude incidence of functional impairment was less for RTX.