Abstract: Objective To investigate the best frequency of hemoperfusion (HP) on cleaning parathyroid hormone (PTH), calcium (Ca2+) and phosphorus (P3+) in maintenance hemodialysis (MHD) patients. Methods A total of 78 MHD patients were recruited. They were randomly assigned into 4 groups: patients in group A were treated with hemodialysis only as the control group (n=18); patients in group B, C and D were treated with the combination of hemoperfusion and hemodialysis (HP+HD), in which HP was performed once a week in group B (n=22), HP twice a week in group C (n=20), and HP once every two weeks in group D (n=18). The treatments were lasted for 12 weeks. Serum Ca2+, P3+, and PTH were measured at the time points of before treatment, 2nd, 4th, 6th, 8th, 10th, and 12th weeks after the treatments. Results Serum PTH decreased after the treatments in all of the 4 groups (P＜0.05). Serum PTH decreased more in groups B, C and D (HP+ HD groups) than in group A (P＜0.05), and more in groups B and C than in group D (P＜0.05). The therapeutic effect was better in group C than in group B at the 4th and 6th weeks after treatment (P<0.05), but was similar between groups B and C at the 2nd, 8th, 10th, and 12th weeks after the treatment. Calcium-phosphorus product decreased gradually in the 4 groups after the treatment, but without significant differences at different time points (P>0.05). Conclusion HP once a week can achieve the cleaning of PTH with relatively lower cost. The higher the HP frequency, the faster the PTH concentration falls at the early stage. The combination of HP+HD can reduce the calcium-phosphorus product, but whether this therapeutic effect is related to HP frequency
is uncertain.

Key words: Hemodialysis, Hemoperfusion, Various Frequencies, Parathyroid Hormone