Clinical and Serologic Factors Associated with Lupus Pleuritis

Abstract

Pleuritis is a common manifestation and independent predictor of mortality in systemic lupus erythematosus (SLE). We examined the prevalence of pleuritis and factors associated with pleuritis in a multicenter Canadian SLE cohort. We studied consecutive adults satisfying the American College of Rheumatology (ACR) classification criteria for SLE who had a completed Systemic Lupus International Collaborating Clinics/ACR Damage Index (SDI) score, at least 1 evaluable extractable nuclear antigen assay, and either a SLE Disease Activity Index (SLEDAI) or a SLE Activity Measure score. Pleuritis was defined as having pleuritis by satisfying the ACR criteria or the SLEDAI. Factors related to pleuritis were examined using univariate and multivariate logistic regression. In our cohort of 876 patients, 91% were women, 65% Caucasian, mean age (+/- SD) was 46.8 +/- 13.5 years, and disease duration at study entry was 12.1 +/- 9.9 years; the prevalence of pleuritis was 34% (n = 296). Notably, greater disease duration (p = 0.002), higher SDI score (p <or= 0.0001), age at SLE diagnosis (p = 0.009), and anti-Sm (p = 0.002) and anti-RNP (p = 0.002) seropositivity were significantly associated with pleuritis. In multivariate analysis with adjustment for disease duration, age at diagnosis, and SDI score, concomitant seropositivity for RNP and Sm were related to a nearly 2-fold greater prevalence of pleuritis (OR 1.98, 95% CI 1.31-2.82). Pleuritis occurred in one-third of this Canadian cohort. Concomitant Sm and RNP seropositivity, greater cumulative damage, longer disease duration, and younger age at SLE disease onset were related to a higher rate of SLE pleural disease.