Long-term outcome of repeated lead chelation therapy in progressive non-diabetic chronic kidney diseases

Background. Previous research suggest that repeated lead-chelation therapy decelerates progression of renal insufficiency in non-diabetic (non-DM) patients with high-normal body lead burden (BLB). Study findings are limited by relatively short-term follow-up and small sample size. Methods. A total of 116 non-DM patients with chronic kidney diseases (serum creatinine level of 1.5-3.9 mg/dl), high-normal BLB (>60 μg and <600 μg) and no lead exposure history were randomly assigned to a chelation or control group in this 4-year clinical trial. For 3 months, the 58 chelation group patients received initial lead-chelation therapy with calcium disodium EDTA, and the 58 control group patients received placebos. During the ensuing 48 months, repeated chelation therapy was administered weekly to chelation group patients unless, on repeated testing, BLB was <60 μg; the control group patients received weekly placebo infusions for 5 weeks at 6-month intervals. Results. Mean change in the glomerular filtration rate (GFR) in the chelation group was -1.8 ± 8.8 ml/min/1.73 m², as compared with -12.7 ± 8.4 ml/min/1.73 m² in the control group (P <0.0001) at study end. Chelation group rates of decline in the GFR was lower than that in the control group, although they had similar decline rates before chelation. At study end, 18 patients, including 15 control group patients, had elevated serum creatinine levels to two times the baseline values. Both Cox and Kaplan-Meier analysis demonstrated repeated chelation therapy was the important determining factor of progression of renal insufficiency. Conclusions. Repeated chelation therapies can, over a four-year period, slow progression of renal insufficiency in non-DM patients with high-normal BLB.