Therapeutic Efficacy and Cost Effectiveness of High Cut-Off Dialyzers Compared to Conventional Dialysis in Patients with Cast Nephropathy

Abstract

Background: High Cut-Off (HCO) dialysis membranes efficiently reduce serum free light chain (FLC) concentrations and may improve renal recovery and survival from multiple myeloma (MM) associated renal failure with cast nephropathy. However, clinical trials comparing dialysis with HCO versus conventional filters are lacking. The aim of this study was to assess clinical outcomes and economic impact of HCO dialyzers compared to conventional hemodialysis membranes in cast nephropathy.

Methods: Multicenter retrospective analysis of 19 patients treated for renal failure from FLC associated cast nephropathy with standard induction chemotherapy (bortezomib/dexamethasone). We compared hemodialysis treatment with High Cut-Off (n = 12) versus conventional dialyzers (n = 7). Primary endpoint was survival; secondary endpoints were renal recovery, renal function and treatment costs.

Results: At 12 months, patient survival was 25% in the HCO group versus 0% in controls (p = NS). A tendency towards faster renal recovery (p = 0.066) and better renal function at 3, 6 and 12 months (p = 0.109) after diagnosis of MM was noted in the HCO group. Complete renal response rate was achieved in 10.5 and 0% of HCO and control patients, respectively, partial renal response in 15.8 and 5.3%, and minor renal response in 26.3 and 15.8%, respectively. Both patient survival and renal recovery were significantly correlated with the extent of free light chain (FLC) reduction in serum. Median treatment costs were CHF 230'000 and 223'000 (p = NS) in the HCO and control group, respectively.

Conclusions: Hemodialysis treatment with HCO membranes for cast nephropathy tended towards better survival as well as faster and better recovery of renal function versus conventional dialyzers. Moreover, total medical costs were comparable between groups. In the absence of results from randomized prospective trials on this topic, the use of HCO dialyzers in patients with renal failure from cast nephropathy may be recommended. Prospective randomized trials are required.

Fig 1. Patient screening and selection chart.

Fig 2. Cost analysis structure.

Fig 3. Time intervals from day of clinical MM diagnosis (= 0) to start of chemotherapy, kidney biopsy and renal replacement therapy (median, 25^th percentile, 75^th percentile, minimum, maximum).

Fig 4. Serum FLC reduction from baseline to day 12 and 21.

Serum FLC reduction from baseline to day 12 and 21 was 23.6% (p = 0.029) and 16.4% (p = 0.024), respectively, in the HCO group versus 19.4% (p = 0.057) and 10.6% (p = 0.047), respectively, in the control group. The differences between treatment groups at both 12 and 21 days were not statistically significant.

Fig 5. Cumulative patient survival.

Kaplan-Meier curve depicting cumulative patient survival censored for death. The solid line represents patients treated with HCO membranes, the dashed line represents patients treated by conventional HD filters. Cox regression analysis was performed with survival as dependent and treatment group (HCO, control) and age as independent variables. P-value for difference between groups was 0.815.

Fig 6. Renal recovery.

Kaplan-Meier curve depicting renal recovery, defined by independence from dialysis, censored for death and end of follow-up. The solid line represents patients treated with HCO membranes, the dashed line represents patients treated by conventional HD filters. Cox regression analysis was performed with renal recovery as dependent and treatments group (HCO, HD) and age as independent variables. P-value for difference between groups was 0.246.

Fig 7. Percentage distribution of total costs in the entire study population.