Objectives: To evaluate disease activity patterns and flare occurrence in a cohort of systemic lupus erythematosus (SLE) patients.
Methods: Patients registered in our lupus Database, diagnosed with SLE between 1991 and 2004 and followed up quarterly from 2004 to 2010 were considered in the study. Disease activity patterns were defined using SLE Disease Activity Index-2000 (SLEDAI-2K), excluding serology, as follows: clinical quiescent disease (CQD), SLEDAI-2K=0 in the three annual visits; minimal disease activity (MDA), SLEDAI-2K=1 in one or more annual visits; chronic active disease (CAD), SLEDAI-2K≥2 in at least two annual visits; relapsing-remitting disease (RRD), SLEDAI-2K≥2 in one out of 3 annual visits. Flare was defined as an increase in SLEDAI-2K≥4 from the previous visit, according to SELENA-SLEDAI flare index.
Results: One hundred and sixty-five patients fulfilled the inclusion criteria. During the 7 year follow-up, 109 (66%) patients experienced at least one period of active disease (CAD, RRD and MDA), whereas 56 patients (34%) had a persistent CQD. The mean±SD number of patients in each pattern per year was: CAD 52.4±5.8 (31.7%), RRD 16.1±6.8 (9.7%), MDA 9.7±1.7, (5.9%), CQD 87±10.5 (52.6%). Annual flare-rate was 0.19 flare per patient/year and mean±SD number of flares was higher in CAD compared with RRD patients (p<0.01). At the multivariate analysis positive anti-dsDNA antibodies, low C3 or C4, male sex, longer lag time between SLE onset and diagnosis, higher number of flares, and use of immunosuppressant were independently associated with active disease including CAD and RRD patterns.
Conclusions: Two-thirds of our patients developed at least one period of active disease during the 7-year follow-up despite tight monitoring and standard treatment.