National registry of patients with systemic lupus erythematosus of the Spanish Society of Rheumatology: objectives and methodology.

OBJECTIVE: To describe the objectives, design and methods of the Spanish Society of Rheumatology systemic lupus erythematosus (SLE) registry (RELESSER).
METHODS: Multicenter, hospital-based registry, with retrospective collection of data from a large representative sample of adult patients with SLE (1997 ACR criteria) attending Spanish rheumatology services. The registry includes demographic data, frequent and infrequent (<1%) clinical manifestations, information about activity, damage, severity, comorbidity, treatments and mortality, collecting 359 variables per patient, with highly standardized definitions. We performed a preliminary descriptive analysis of the data.
RESULTS: Forty-five centers were involved and 4,024 SLE patients (91% with ≥ 4 ACR criteria) have been included; 90% are women and 93% caucasians, with a median age at diagnosis of 33 years, median disease duration: 120 months, median follow-up duration: 104 months; 3,222 (81%) of the patients are in active follow-up and 591 (14%) were lost to follow-up. The median values of the SELENA-SLEDAI score, SLICC/ACR damage index and Katz severity index have been 2, 1 and 2, respectively. A total of 211 patients (6%) died.
CONCLUSIONS: RELESSER represents the largest European SLE registry built to date, providing comprehensive and reliable information on SLE manifestations, disease status, comorbid conditions and treatments in daily clinical practice. RELESSER is constituted as a tool of great potential for multicenter clinical research in SLE.