AB0344 PREVALENCE AND RISK FACTORS FOR SEROSITIS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A CASE CONTROL STUDY

Background: Systemic lupus erythematosus (SLE) is an autoimmune multisystemic disease with a wide variety of clinical manifestations, being one of them serositis, which includes pericarditis, pleuritis and peritonitis [1]. Incidence of serositis ranges between 11-54% [2]. Objectives: To determine the prevalence of serositis in patients (pt) with SLE attended at the outpatient Lupus Unit and identify factors that could be used as predictors of this manifestation. Methods: Retrospective case-control study. 297 medical records of SLE pt were reviewed: 28 pt were diagnosed with serositis (cases) and were age- and sex-matched with 2 controls with SLE without serositis. Differences between cases and controls were analyzed as well as factors associated with serositis. Results: Patient’s characteristics are described in Table 1. The prevalence of serositis in our cohort was 9.42%. The difference between the prevalence of serositis in men and women was statistically higher in men, 30% vs 7.9% (p=0.001, CI 95%: 1.7%-42.4%). Serositis was diagnosed at an age of 41 ±14 years (y) and in 40.7% it was the first symptom. Time from SLE diagnosis to serositis was 4±5.3 y. 10 pt had recurrences: 6 had 2, and 4 had 3. Incidence of pericarditis and pleuritis was 78.6% and 82.1% respectively. 2 pt suffered from pericardial tamponade. Mean prednisone dose received during the serositis was 44.6±26.6mg. At the moment of serositis 100% were ANA+, 85.7% antidsDNA+, 80% CrithidiaDNA+, 57.9% antiRo60+, 52.6% antiRo52+, 15.9% antiLa+, 47.4% antiRNP+, 21.1% antiSm+, and 77.8% had low C3. When looking for serositis-associated factors we only found association with antidsDNA measured by Crithidia (p=0.016) and different measures of glucocorticosteroids (GC), having cases needed higher doses than controls (Table 1). Those with serositis had significantly received more mycophenolic acid (p=0.021) and marginally, more belimumab (p=0.056). Conclusion: The prevalence of serositis was 9.42%. Serositis is significantly more frequent in SLE men than in women: almost ⅓ will develop serositis, so we need greater awareness of serositis in SLE men. CrithidiaDNA+ was identified as an associated factor of serositis. Furthermore, pt with serositis significantly received more pulses of GC and a higher maximum dose throughout the disease, which could imply a more aggressive form of SLE than in those without serositis. No correlation was found between serositis and any other characteristic. References: [1]Hochberg MC. Updating the American College of Rheumatology revised criteria for the classification of systemic lupus erythematosus. Arthritis Rheum 1997;40:1725 [2]Ryu S, Fu W, Petri MA: Associates and predictors of pleurisy or pericarditis in SLE. Lupus. Science. 2017, 4(1):e000221. Disclosure of Interests: None declared