Plasma exchange when myeloma presents as acute renal failure: a randomized, controlled trial

Two small, randomized trials provide conflicting evidence about the benefits of plasma exchange for patients with acute renal failure at the onset of multiple myeloma.

To assess the effect of 5 to 7 plasma exchanges on a composite outcome in patients with acute renal failure at the onset of multiple myeloma.

Randomized, open, controlled trial, stratified by chemotherapy and dialysis dependence, conducted from 1998 to 2004.

Hospital plasma exchange units in 14 Canadian medical centers.

104 patients between 18 and 81 years of age with acute renal failure at the onset of myeloma.

Study participants were randomly assigned to conventional therapy plus 5 to 7 plasma exchanges of 50 mL per kg of body weight of 5% human serum albumin for 10 days or conventional therapy alone. Ninety-seven participants completed the 6-month follow-up.

The primary outcome was a composite measure of death, dialysis dependence, or glomerular filtration rate less than 0.29 mL x s(-2) x m(-2) (<30 mL/min per 1.73 m2).

At enrollment, the plasma exchange and control groups were similar for dialysis dependence, chemotherapy, sex, age, hypercalcemia, serum albumin level, 24-hour urine protein level, serum creatinine level, and Durie-Salmon staging. The primary composite end point occurred in 33 of 57 (57.9%) patients in the plasma exchange group and in 27 of 39 (69.2%) patients in the control group (difference between groups, 11.3% [95% CI, -8.3% to 29.1%]; P = 0.36). One third of patients in each group died.

The study was small, used a composite outcome, and did not use renal biopsy as an inclusion criterion. Recruiting physicians were blinded to treatment allocation but not to treatment thereafter.

In patients with acute renal failure at the onset of multiple myeloma, there is no conclusive evidence that 5 to 7 plasma exchanges substantially reduce a composite outcome of death, dialysis dependence, or glomerular filtration rate less than 0.29 mL.s(-2).m(-2) (<30 mL/min per 1.73 m2) at 6 months.