Scrutinizing the Heterogeneity of SLE: Defining Phenotypes

Specific aims of this study are: 1. To test the clinical impression of the disease courses by modeling the course of the disease in each of three sub-populations of patients where it is anticipated that one sub-population will experience relapsing and remitting disease activity, one will experience persistently active disease and another will exhibit a monophasic pattern. 2. To develop predictive models for group membership to enhance the accuracy of prognosis. 3. To test these models in the inception cohort of SLE patients within the Toronto Lupus Cohort. Study Design: Retrospective longitudinal observational cohort Patients will be categorised into three disease courses: I. Relapsing-remitting II. Persistently active III. Monophasic Relapsing/remitting is defined as periods of disease activity SLEDAI-2K of 4 or more, (but if only 4 cannot be from serology alone) less than 50% of the time alternating with periods of inactivity (SLEDAI-2K \<4) over the course of follow-up. Persistently active disease is defined as SLEDAI-2K of 4 or more, (but if only 4 cannot be from serology alone), in greater than 80% of the visits, or no 2 consecutive visits with SLEDAI-2K \< 4. Monophasic course is defined as disease activity SLEDAI-2K of 4 or more, (but if only 4 cannot be from serology alone) for an initial period of less than 3 years followed by resolution and inactive disease (SLEDAI-2K of 0 excluding serology) for at least 5 years. Clinical and laboratory characteristics, therapies and outcomes for each subgroup will be described. Identification of all clinical and laboratory features of lupus contained in the CRF will be compared for each group, as well as the medications prescribed.