Dialysis arthropathy, beta 2-microglobulin and the effect of dialyser membrane

Patients with dialysis arthropathy had the greatest mean serum beta 2-microglobulin (59.5 mg/l) but there was no threshold concentration of beta 2-microglobulin above which all patients developed dialysis arthropathy. Haemodialysis patients without dialysis arthropathy and patients on continuous ambulatory peritoneal dialysis (CAPD) also had grossly elevated values of beta 2-microglobulin (47.9 mg/l and 30.7 mg/l respectively). There was a significant positive correlation between duration of treatment and serum beta 2-microglobulin for the patients treated by haemodialysis, but this was not the case for patients on CAPD. There was a significant negative correlation between residual urinary volume and serum beta 2-microglobulin for the patients on haemodialysis without dialysis arthropathy, and also for the patients on CAPD. This was not true for the patients with dialysis arthropathy. Both duration of treatment and residual urine volume correlated with serum beta 2-microglobulin, and therefore an analysis of covariance was used to take account of this in comparing the groups. This showed that there was no difference between serum beta 2-microglobulin in haemodialysis patients with and without dialysis arthropathy. However, CAPD patients had a significantly lower corrected mean serum beta 2-microglobulin. Haemodialysis with cuprophane membranes was associated with an increase in beta 2-microglobulin of 11.5%, whereas haemodialysis with polycarbonate was associated with a decrease of 6.8% at 6 h.(ABSTRACT TRUNCATED AT 250 WORDS)