Serum beta 2-microglobulin levels in patients chronically dialyzed with CA-210 versus CT-190 dialysis membranes

beta 2-Microglobulin (B2M) amyloidosis (dialysis-related amyloidosis), manifested primarily by carpal tunnel syndrome and destructive osteoarthropathy, is a major sequel of long-term dialysis. Previous investigators have shown that high-flux biocompatible synthetic membranes (e.g., polyacrylonitrile) lower beta 2M levels when compared to cellulosic membranes (e.g., cuprophane). To date, however, no study has compared beta 2M levels of patients dialyzed with the two more biocompatible cellulosic membranes CA-210 (cellulose acetate) and CT-190 (cellulose triacetate; high flux, more biocompatible). We retrospectively compared the serum beta 2M levels in two chronic hemodialysis populations: 22 patients on CT-190 and 21 patients on CA-210. There was no difference between the two groups with regard to age, sex, or duration of dialysis. The patients on the CA-210 membrane had significantly higher serum beta 2M levels (mean +/- SE; 53.6 +/- 4.7 vs. 36.8 +/- 2.6 mg/l, CA-210 vs. CT-190, respectively, p = 0.003). Subsequently we switched 13 patients dialyzed with a CA-210 membrane to a CT-190 membrane and followed serum beta 2M levels for 14 months. We found a significant decrease in serum beta 2M levels within 1 month which was maintained over 14 months of follow-up (47.4 +/- 4.4 vs. 62.8 +/- 6.7 mg/l, CT-190 at 14 months vs. CA-210 at baseline, respectively, p < 0.01).