Extrarenal disease activity in systemic lupus erythematosus is not suppressed by chronic renal insufficiency or renal replacement therapy

Objective. To assess whether chronic renal impairment (CRI) and/or renal re placement therapy (RRT) in systemic lupus erythematosus (SLE) are associate d with reduced extrarenal SLE activity. Methods. This was a retrospective cohort analysis of patients with SLE who are followed at the University of Toronto Lupus Clinic. Patients with SLE w ere studied in 2 stages; chronic renal insufficiency (defined as a serum cr eatinine > 200 mu mol/l for > 6 months) and following the institution of di alysis therapy. Controls consisted of the next 2 age and sex matched patien ts in the clinic with a history of lupus nephritis who had not developed re nal insufficiency. We assessed the flare rate tan increase in nonrenal SLED AI greater than or equal to 1.0) for patients and controls in the first 12 months of followup at the clinic in each stage. Results. Twenty-one patients, 17 female and 3 male, were followed through 2 5 episodes of CRI or RRT as were 50 controls. In the CRI stage (n = 12), fl ares occurred in 8 (67%) within one year compared to 14 (58%) of 24 control s (p = NS). In the RRT stage (n = 13), flares occurred in 7 (54%) compared to 16 (62%) of 26 controls (p = NS). The magnitude as well as the character istics of the flares did not differ between patients and controls in either stage. Conclusion. Patients with SLE who develop CRI, or who receive RRT, continue to display evidence of ongoing extrarenal disease activity. Such patients require careful longterm followup for management of their extrarenal diseas e.