Dialysis Arthropathy, {beta}2-Microglobulin and the Effect of Dialyser Membrane

Patients with dialysis arthropathy had the greatest mean serumß₂-microglobulin (59.5 mg/l) but there was no thresholdconcentration of ß₂-microglobulin above which allpatients developed dialysis arthropathy. Haemodialysis patientswithout dialysis arthropathy and patients on continuous ambulatoryperitoneal dialysis (CAPD) also had grossly elevated valuesof ß₂-microglobulin (47.9 mg/l and 30.7 mg/l respectively).There was a significant positive correlation between durationof treatment and serum ß₂ for the patients treatedby haemodialysis, but this was not the case for patients onCAPD. There was a significant negative correlation between residualurinary volume and serum ß₂-microglobulin for thepatients on haemodialysis without dialysis arthropathy, andalso for patients on CAPD. This was not true for the patientswith dialysis arthropathy. Both duration of treatment and residualurine volume correlated with serum ß₂-microglobulin,and therefore an analysis of covariance was used to take accountof this in comparing the groups. This showed that there wasno difference between serum ß₂-microglobulin in haemodialysispatients with and without dialysis arthropathy. However, CAPDpatients had a significantly lower corrected mean serum ß₂-microglobulinHaemodialysis with cuprophane membranes was associated withan increase in ß₂-microglobulin of 11.5%, whereashaemodialysis with polycarbonate was associated with a decreaseof 6.8% at 6 h. Our results provide circumstantial evidencethat repeated haemodialyses with cupro phane membranes may predisposelong-term haemo dialysis patients to dialysis arthropathy. CAPDpatients have lower ß₂-microglobulin concentrationsand may be less likely to develop dialysis a Long-term prospectivestudies are needed to confirm these assertions.