In order to measure lupus activity, we will use a validated disease activity index, the Systemic Lupus Erythematosus disease activity index (SLEDAI) (26). The primary outcome will be global disease activity throughout the follow-up period, estimated as the area under the SLEDAI-curve (SLEDAI-AUC). Secondary outcomes will be the incidence of lupus flares, the time to the first flare, changes in SLEDAI values from baseline at each follow-up visit, and maximum disease activity. Lupus flares and severe flares are defined as an increase in the SLEDAI of 3 or more or 12 or more points, respectively, from the previous visit (27). The data will also be analyzed with the use of a new version of the SLEDAI (SLEDAI-2K) (28), and a modified SLEDAI (SLEDAIm) that excludes microhematuria and pyuria because they may be associated with the treatment. We will also record lupus treatment, hospitalizations, thromboses, and deaths.