Background ILD may present as a rare but serious extraarticular manifestation in patients with RA and can have dramatic effect on morbidity and mortality.
Objectives To evaluate the course of pulmonary disease in a large prevalence cohort of patients with RA who have ILD.
Methods Prevalent cases of RA with ILD from 01/01/1998 to 01/01/2014 were identified in a single center's electronic medical record using advanced software to identify cases using ICD-9 diagnosis codes. All cases were manually reviewed and screened for inclusion. RA characteristics and pulmonary findings including high-resolution computed tomography (HRCT) and pulmonary function testing (PFT) were evaluated. Descriptive statistics were used to summarize the data.
Results Two-hundred and one patients with ILD and RA were identified. Patients were predominately Caucasian (97%); 54% were males; mean age was 66.6 years (±10.9) at ILD diagnosis. Mean follow-up from ILD diagnosis was 4.1 years (±4.0) and median time from RA to ILD diagnosis was 4.9 (range -15.7 to 45.6) years. Seventy-three (37%) were never smokers. Eighty-seven (43%) had usual interstitial pneumonia (UIP) and/or idiopathic pulmonary fibrosis (IPF) and sixty-seven (33%) had non-specific interstitial pneumonia (NSIP) by HRCT. Anti-citrullinated protein antibody (ACPA) was present in 110 (77%) of 142 tested patients, and rheumatoid factor (RF) was present in 161 (84%). Erosive disease was present in 52 (28%) of patients and 103 (51%) had other extraarticular manifestations of RA prior to or at time of ILD diagnosis. The baseline predicted PFTs at time of ILD diagnosis included a forced vital capacity (FVC) of 72% (± 21), a forced expiratory volume in 1 second (FEV1) of 71% (±21), and a diffusing capacity for carbon monoxide (DLCO) of 55% (±19). Ninety-four (49%) patients required supplemental oxygen with a mean requirement at last followup of 2.9 liters (±1.6). At last follow-up 79 had died, with pulmonary disease accounting for 23 (29%) of deaths.
Conclusions In this largest single-center reported cohort of patients with RA-ILD, most patients were seropositive, male, and had a prior history of tobacco use. UIP was more common than NSIP. Almost half of patients required supplement oxygen, and nearly one third died from pulmonary disease which was the most common known cause of death.
Disclosure of Interest None declared