NEW YORK (Reuters Health) – Based on the limited evidence available, adjuvant plasma exchange may reduce the risk of end-stage renal disease in patients with renal vasculitis or rapidly progressive glomerulonephritis, an international team reports.

The findings are based on a meta-analysis of nine randomized trials comparing standard care to standard care plus plasma exchange in a total of 387 such patients.

Writing in the American Journal of Kidney Diseases for April, Dr. Michael Walsh, at McMaster University, Hamilton, Canada, and colleagues note that most cases of rapidly progressive glomerulonephritis have circulating antineutrophil cytoplasmic antibodies (ANCAs) present.

Outcomes of this form of ANCA-associated vasculitis have improved with the introduction of immunosuppressive therapy and glucocorticoids, the team notes, but rates of end-stage renal disease (ESRD) and death are still high. Plasma exchange aimed at removing ANCAs has been studied in several clinical trials.

In the current analysis, the pooled data covered 201 patients who were treated with plasma exchange and 186 who were not. The number of plasma exchange treatments given ranged from 4 to 28, given over 1-8 weeks. Albumin was the most common replacement fluid.

No individual study showed a significant difference between the two groups in the primary composite outcome of ESRD or death, but the pooled relative risk for patients using plasma exchange compared with those not using plasma exchange was 0.80 (p=0.04), the researchers found

However, they point out, “Although the primary result of this meta-analysis was statistically significant, the calculated optimal information size suggests that at least 1,478 patients are required to be confident that plasma exchange provides at least a 25% RR (relative risk) reduction.”

Furthermore, plasma exchange had a large effect on ESRD (RR 0.64) but not on mortality (RR 1.01). This may be because survival in kidney failure caused by ANCA-related vasculitis is reasonably good with dialysis or transplantation, the authors suggest.

They conclude that plasma exchange is promising, but until more clinical trial data are available, “widespread use of plasma exchange for patients with renal vasculitis cannot be endorsed because of its expensive, resource-intensive, and invasive nature.”

Reference:

Plasma Exchange for Renal Vasculitis and Idiopathic Rapidly Progressive Glomerulonephritis: A Meta-analysis
Am J Kidney Dis; 2011;57:566-574.