Fresenius F60 polysulfone dialyzer was used for HFHD group, and Fresenius F6HPS polysulfone dialyzer was used for LFHD group.

• HFHD组使用聚砜膜F60高通量透析器，LFHD组使用聚砜膜低通量F6HPS透析器，连续观察1年。