Background/Purpose: Systemic lupus erythematosus (SLE) is a disease with a variety of  clinical manifestations but interestingly interstitial lung disease (ILD) is rare. The literature to date has not identified consistent markers to help with clinical decision making regarding screening for SLE-ILD.  Some of these features may depend on specific ethnic variation based on the population studied.  We retrospectively identified patients with SLE and ILD at our institution over a twenty-year period to try to identify an SLE-ILD phenotype in our Northwest US SLE population to aid in decisions about screening.

Methods: We conducted a review of our electronic record database at University of Washington Medical center, looking for patients with the diagnosis of SLE who were seen between 1998-2018 in our Rheumatology outpatient clinics.  We identified 1335 SLE patients by using the International Classification of Diseases (ICD) 9 and 10 codes.  We also identified 29 patients with a diagnosis of SLE-ILD.   Diagnosis was confirmed by individual medical record review by a rheumatologist based on history, exam, laboratory, and imaging findings.  Clinical and serologic data for each patient was recorded and analyzed and compared to a control group of SLE patient without ILD.

Results: SLE-ILD was found in only 2% of our SLE population.  SLE-ILD appears to be more common in Asians (31 vs 14% SLE-ILD vs control population).   More than half of the patients who will develop SLE-ILD, will develop it in first 2 years after SLE diagnosis. NSIP is the most common type of SLE-ILD (72.2%) followed by UIP (24%). Common clinical features include the presence of Raynaud’s phenomenon (RP) and gastrointestinal esophageal reflux disease (GERD) and both were present in greater than 70% of SLE-ILD patients.  Of note, 34% of our SLE-ILD patients had co-existing pulmonary hypertension.  Chest x-ray missed ILD changes in almost 30% and required CT scan to make the diagnosis. Common serologic findings included speckled ANA (66%), anti-SM, RNP or SM/RNP antibodies (59%). Seventy-four percent of patients responded (stable or improved) to therapy (most common therapy was MMF).  Forced vital capacity measurement (FVC) changed at an average rate of only 1.65 %/year in this population.  Those with a UIP pattern on CT tended to do worse (43% worse UIP vs 19% NSIP).  Only one death occurred in this population over the study period of unknown cause.

Conclusion: Our retrospective study showed that ILD is a rare manifestation of SLE. Patients with the combination of RP, GERD, and either anti-SM, RNP, or SM/RNP antibodies should be considered high risk for developing SLE-ILD and intermittent screening with pulmonary function tests that include FVC and DLCO measurements.  Given that 41% of our patients also had pulmonary hypertension ECHO should also be considered in patients with SLE-ILD especially those with relatively low DLCO. Screening should be considered early in the disease process in patients with this phenotype and Asian patients especially should be watched closely.

« Back to 2019 ACR/ARP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/interstitial-lung-disease-in-patients-with-systemic-lupus-erythematosus-who-should-we-screen/