Amyloid bone disease and highly permeable synthetic membranes

The effect of different highly permeable membranes on amyloid bone disease (ABD) was retrospectively evaluated in patients on renal replacement therapy (RRT) in our Unit with a dialytic age of more than 4 years. A group of 36 patients (age 60 +/- 12 years) after a variable period (28 +/- 29 months) on hemodialysis with cuprophane membrane (CU-HD), were moved to HDF with a reinfusate volume of 22 +/- 1 1/session, for a period of 65 +/- 26 months using the following membranes: AN69 1.6 m2, PAN 1.8, PMMA 2.1, PS 1.3, polyamide (PA) 1.3 and 1.6. Bone x-rays of wrists, hips and shoulders were taken annually and the presence of ABD was evaluated according to generally accepted criteria. ABD occurred in 4 patients after a period of 73 +/- 30 months on CU-HD only; it developed in 4/7 patients an AN69, in 4/6 on PAN, in 3/5 on PMMA, in 3/5 on PS; no patient of the 13 on PA developed ABD. Comparing patients on PA with those on other synthetic membranes, no significant difference was found in dialysis time (73 +/- 19 vs 83 +/- 28 months) as well as in age (59 +/- 13 vs 61 +/- 11 years) at ABD on set, when present. These data strongly encourage prospective studies enrolling more patients for a longer period of observation in order to evaluate possible differences on ABD development among various synthetic membranes.