Immunosuppressive agents have become the standard of therapy for proliferative lupus nephritis, but some patients may relapse after discontinuing treatment. We reviewed the cases of renal flares in a cohort of patients who participated in 2 randomized controlled clinical trials at the National Institutes of Health and explored the prevalence, outcome, and predictive factors of renal flares.
Data were obtained on 145 patients treated with pulse cyclophosphamide, pulse methylprednisolone, or the combination of both. Patients had not received immunosuppressive therapy for at least 6 months and had experienced complete or partial response according to defined criteria. Renal flares were classified as either proteinuric or nephritic based on changes in urinary protein and sediment. Most patients who experienced a flare received additional immunosuppressive therapy.
Seventy-three patients had a complete response, and 19 had partial response/stabilization. Forty-one of these patients (45%) experienced renal flares (nephritic in 33, proteinuric in 8) after a mean followup of 117 months; 31 of them received additional immunosuppressive therapy. The median time to renal flare was 36 months in the complete responders and 18 months in the partial responders. Eleven of the 41 patients (27%) progressed to end-stage renal disease (ESRD); 9 had nephritic flares (all severe except for 1) and 2 had proteinuric flares (1 in each responder group). Compared with patients who had a complete response, those with a partial response were more likely to experience a flare, to have a severe nephritic flare, or to progress to ESRD. Low C4 at the time of response and African American ethnicity were significant independent risk factors for renal flare, by multivariate Cox proportional hazards analysis.
Nephritic flares are common in patients with proliferative lupus nephritis, even in those with a complete response to therapy, but they do not necessarily result in loss of renal function if treated with additional immunosuppressive agents. Renal flares are an important feature of the natural history of lupus nephritis and provide an opportunity for additional preventive strategies, as well as measures of efficacy in future therapeutic trials.