Clinical and Therapeutic Characteristics of a Spanish Systemic Lupus Erythematosus Cohort: Comparison with the RELESSER Registry.

INTRODUCTION

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by marked clinical and therapeutic heterogeneity. In Spain, patient care is primarily shared between Rheumatology and Internal Medicine departments. The characterization of local patients series and their comparison with national registries allows clinical profiles and management patterns to be contextualized across different healthcare settings.

METHODS

A retrospective cross-sectional study was conducted including all patients with SLE under active follow-up in a specialized autoimmune diseases unit within the Department of Internal Medicine at a Spanish tertiary hospital between 2024 and 2025. Demographic, clinical, immunological, and therapeutic variables were analyzed. Findings were compared with previously published data from the Spanish Society of Rheumatology's Systemic Lupus Erythematosus Registry (RELESSER).

RESULTS

A total of 305 patients were included, predominantly women (89.8%), with a mean age at diagnosis of 34.2±15.4 years and a mean disease duration of 15.7±11.8 years. Musculoskeletal (83.3%) and mucocutaneous manifestations (79.3%) were the most frequent, followed by hematological (38.4%) and renal involvement (29.5%). Disease activity and accumulated damage were low [SLEDAI 2 (0-4), SLEDAIc 0 (0-1), SDI 0 (0-1)]. Compared with RELESSER, our series showed longer disease duration, higher use of antimalarials, lower exposure to corticosteroids and conventional immunosuppressive agents, and a higher use of biologic therapies.

CONCLUSIONS

This single-center registry shows overall clinical characteristics comparable to those reported in RELESSER, with relevant differences in treatment patterns, reflecting the variability in SLE management in real-world clinical practice.