The quality of evidence is downgraded by study limitations (unclear allocation concealment and blinding) and by imprecise results (few patients and outcome events).
A Cochrane review [Abstract]1 included 40 studies with a total of 3 764 subjects to evaluate the benefits and harms of any intervention used for the treatment of renal vasculitis in adults.
Induction therapy: Plasma exchange as adjunctive therapy reduced the need for dialysis at 3 (RR 0.43, 95% CI 0.23 to 0.78; 2 studies, n=147) and 12 months (RR 0.45, 95% CI 0.29 to 0.72; 6 studies, n=235), but made little or no difference to death, serum creatinine, sustained remission or to serious or the total number of adverse events. It increased the number of serious infections (RR 1.26, 95% CI 1.03 to 1.54; 5 studies, n=956).
Remission rates for pulse and continuous cyclophosphamide (CPA) were equivalent but pulse treatment increased the risk of relapse (RR 1.79, 95% CI 1.11 to 2.87; 4 studies, n=235) compared to continuous CPA. Leukopenia was less common and nausea more common with pulse treatment.
Rituximab made little or no difference to death, remission, relapse, serious infections, or severe adverse events compared to CPA. A single study reported no difference in the number of deaths, need for dialysis, or adverse events between mycophenolate mofetil (MMF) and CPA. Remission was reported to improve with MMF but more patients relapsed.
A lower dose of steroids was probably as effective as high dose and caused fewer infections.
Maintenance therapy:Azathioprine (AZA) had equivalent efficacy to CPA with fewer episodes of leucopenia. MMF resulted in a higher relapse rate compared to azathioprine in remission maintenance. Rituximab was an effective remission induction and maintenance agent. There were fewer relapses but more serious adverse events with leflunomide compared to methotrexate.
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