Therapeutic effect of high-efficiency online hemodiafiltration for recurrent restless legs syndrome in dialysis patients

Two dialysis patients developed recurrent restless legs syndrome. The clinical courses and the association between the α(1)-microglobulin removal rate and the therapeutic effects of hemodiafiltration were analyzed. Case 1: a middle-aged woman was switched from predilution online hemodiafiltration to hemodialysis, following which the α(1)-microglobulin removal rate decreased from 39.1 to 29.9%. A month later, the severe restless legs syndrome occurred. The treatment was then switched to high-efficiency hemodiafiltration and 2 weeks later, these symptoms were resolved. The α(1)-microglobulin removal rate increased to 41.9%. Her symptoms recurred 5 years later with severity; thus, the hemodiafiltration treatment conditions were changed. Under revised conditions, the α(1)-microglobulin removal rate was 42.6%, and her symptoms were alleviated. Continuation of high-efficiency hemodiafiltration led to the resolution of the syndrome at 1 month after recurrence. Case 2: a middle-aged man on hemodialysis developed the restless legs syndrome in the second year of treatment. The α(1)-microglobulin removal rate was 23.8%. After switching to a month-long high-efficiency hemodiafiltration with a removal rate of ≥ 40%, his symptoms were resolved. However, the syndrome recurred after a year with severity. The symptoms were alleviated using various measures. The hemodiafilters were changed, and hemodiafiltration with an α(1)-microglobulin removal rate of ≥ 40% was continued; 2 months later, his symptoms resolved. High-efficiency online hemodiafiltration is an effective therapeutic strategy for restless legs syndrome in dialysis patients. We found, for the first time, that target removal efficiency is an α(1)-microglobulin removal rate of 40% or higher. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10047-020-01164-1) contains supplementary material, which is available to authorized users.