Background: There is limited evidence to support cytotoxic therapy in patients with IgA nephropathy and renal insufficiency. We studied the effect of cytotoxic therapy in patients with IgA nephropathy and renal insufficiency, and evaluated possible predictors of response.
Methods: Retrospective analysis of patients with IgA nephropathy who received immunosuppressive therapy. The primary outcome measure was progression of renal disease, defined as an increase in serum creatinine levels of ≥ 50% or development of end-stage renal disease.
Results: From 1996 to 2008, 19 patients with biopsy-proven IgA nephropathy were treated with cytotoxic agents and prednisone because of renal insufficiency and/ or severe proteinuria. Characteristics of patients at the start of therapy: age 42±11 years, serum creatinine 208 (96-490) μmol/l, estimated glomerular filtration rate (eGFR) 33 (12-65) ml/min/1.73 m2, and protein- creatinine ratio 3.8 (0.6-18.2) g/10 mmol. Follow-up after initiation of therapy was 35 (7-133) months. Ten patients had progressive renal disease, whereas eGFR was stable in nine. Serum creatinine levels and proteinuria at the start of treatment were not significantly different between responders and non- responders. Proteinuria response at six months after start of therapy proved a good predictor: proteinuria decreased by ≥ 50% and/or reached levels below 1 g/day in 8/9 responders. In contrast, proteinuria decreased by more than 50% and reached levels < 1 g/day in only 3/10 non-responders (p < 0.01).
Conclusion: Prolonged immunosuppressive therapy with cytotoxic agents and prednisone may benefit a subgroup of patients with progressive IgA nephropathy. A reduction of proteinuria ≥ 50% to levels below 1 g/day within six months predicts a favourable long-term response.