Impact of High-Cut-Off Dialysis on Renal Recovery in Dialysis-Dependent Multiple Myeloma Patients: Results from a Case-Control Study

BACKGROUND: High-cut-off hemodialysis (HCO-HD) can effectively reduce high concentrations of circulating serum free light chains (sFLC) in patients with dialysis-dependent acute kidney injury (AKI) due to multiple myeloma (MM). Therefore, the aim of this study was to analyze renal recovery in a retrospective single-center cohort of dialysis-dependent MM patients treated with either conventional HD (conv. HD) or HCO-HD. METHODS AND RESULTS: The final cohort consisted of 59 patients treated with HCO-HD (n = 42) or conv. HD (n = 17). A sustained sFLC response was detected in a significantly higher proportion of HCO-HD patients (83.3%) compared with conv. HD patients (29.4%; p = 0.007). The median duration of sFLC required to reach values <1000 mg/l was 14.5 days in the HCO-HD group and 36 days in the conv. HD group. The corresponding rates of renal recovery were 64.3% and 29.4%, respectively (chi-squared test, p = 0.014). Multivariate regression and decision tree analysis (recursive partitioning) revealed HCO-HD (adjusted odds ratio [OR] 6.1 [95% confidence interval (CI) 1.5–24.5], p = 0.011) and low initial uric acid values (adjusted OR 1.3 [95%CI 1.0–1.7], p = 0.045) as independent and paramount variables associated with a favorable renal outcome. CONCLUSIONS: In summary, the results from this retrospective case-control study suggest in addition to novel agent-based chemotherapy a benefit of HCO-HD in sFLC removal and renal outcome in dialysis-dependent AKI secondary to MM. This finding was especially pertinent in patients with low initial uric acid values, resulting in a promising renal recovery rate of 71.9%. Further prospective studies are warranted.