Environmental Exposure to Lead and Its Health Effects on Patients With Maintenance Hemodialysis

One thousand patients with LHD who have no history of exposure to lead will be observed for 18 months. Blood lead level(BLL), biochemical data, hemoglobin, albumin, Cr, high sensitivity C-reactive protein (HsCRP), and blood cell counts are assessed at baseline. The morbidity and mortality are recorded in detail. Then, one hundred subjects with high BLL (>20μg/dl) will be randomly assigned to the study and control groups. For 3-6 months, the 50 patients in the study group will receive lead-chelation therapy with calcium disodium EDTA weekly until the BLB falls below BLL< 5 μg/dl, and the 50 control group patients receive weekly placebo for 12 weeks. During the ensuing 18 months, the BLL, biochemical data will be regularly followed up every 3 months. BLL is measured every 6 months. If BLL of the study group patients increase >10 μg/dl, the chelation therapy will be performed again until their BLL is <5 μg/dl. The primary end point is morbidity or mortality during the observation and follow-up period. A secondary end point is the change in hemoglobin, albumin, Cr and Hs CRP during the follow up period.