Disease characterization of systemic lupus erythematosus (SLE) patients in Quebec

Objective Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by an array of organ manifestations that can appear during flares and disappear during remissions. The objectives of this study were: (i) to examine SLE manifestation groups longitudinally in an SLE cohort; and (ii) to assess the association between early antimalarial treatment and renal manifestations. Methods Seven SLE manifestation groupscutaneous, hematologic, lung, musculoskeletal, neuropsychiatric, serositis, renalwere tracked using Kaplan-Meier survival curves in an incident SLE cohort from Quebec health administrative data (n=2010). A subgroup with provincial drug insurance coverage was followed over time to examine the association between early antimalarial treatment (within three months after SLE diagnosis) and renal manifestations using a Cox proportional hazards survival model. Results Cutaneous manifestations was the most common manifestation at SLE diagnosis (30.0%, 95% CI: 27.7-32.2%). About two-thirds (66.2%, 95% CI: 63.4-68.9%) of patients had evidence of at least one SLE manifestation at diagnosis, which increased to 87.2% (95% CI: 84.2-90.3%) by the end of follow-up. After adjusting for age, sex, early concomitant systemic steroid therapy, Charlson comorbidity index, primary care visits in the year prior and other SLE manifestations at baseline, no statistically significant association was established between antimalarial therapy and renal manifestations. Conclusion This study provides insight regarding organ manifestations within a population-based sample. Most patients identified with SLE had other diagnostic evidence that supports an underlying diagnosis of SLE. No protective effects for antimalarial agents against renal manifestations could be established in this population-based cohort.