Controlled prospective trial of prednisolone and cytotoxics in progressive IgA nephropathy

Abstract

In a single-center, multiple-referral source study, 38 patients with progressive IgA nephropathy and controlled hypertension were randomized to treatment with prednisolone and cytotoxic agents, to therapy with low-dose cyclophosphamide then azathioprine, and to control groups. The follow-up period lasted 2 to 6 yr. Renal survival, as assessed by Kaplan-Meier analysis annually to 5 yr, showed significant preservation of function from 3 yr in the treatment group and 82, 82, 72, and 72% for 2, 3, 4, and 5 yr, respectively, compared with 68, 47, 26, and 6% in controls. Rate of loss of renal function, evaluated objectively by least-squares analyses of reciprocal serum creatinine, was reduced-and in one-third of the patients, arrested-during immunosuppressive treatment. Proteinuria, present in all patients at the time of entry into the trial, was reduced by treatment from 12 mo, compared with pretreatment levels or controls; erythrocyturia was reduced from 6 mo. Histologic activity and chronicity indexes were determined in renal biopsies performed at trial entry. Multivariate analysis demonstrated that mesangial cell proliferation and matrix scores were highest in those patients with more rapidly progressive disease. No morphologic variable or residual renal function predicted response to immunosuppressive therapy at entry. Mean arterial pressures did not differ significantly between treatment and control groups. There was thus no explanation other than treatment for the improved outcome in patients who received immunosuppressive therapy. Morbidity attributable to treatment or to renal failure occurred in both groups; an audit showed that benefits of therapy outweighed expected or minor side effects of drugs in this population at risk of end-stage renal failure. Patients selected for moderately progressive IgA nephropathy benefit from treatment with prednisolone and cytotoxic agents; results are consistent with modulation of systemic immune response or nephritic injury, thus explaining improved outcome, and indicate that this therapy has an acceptably low risk of side effects.