Effect of chelation therapy on progressive diabetic nephropathy in patients with type 2 diabetes and high-normal body lead burdens.

BACKGROUND

A previous study in type 2 diabetic patients with high-normal body lead burdens showed that EDTA chelation therapy for 3 months slows progressive diabetic nephropathy during a 12-month follow-up. The effect of a longer course of therapy on kidney function decrease over a longer follow-up is not known.

STUDY DESIGN

A 12-month run-in phase, then a randomized single-blind study with a 27-month intervention.

SETTING & PARTICIPANTS: University medical center; 50 patients (serum creatinine, 1.5-3.9 mg/dL) with high-normal body lead burden (≥80-<600 μg) were randomly assigned to the treatment and control groups.

INTERVENTION

The treatment group received weekly chelation therapy for 3 months to reduce their body lead burden to <60 μg and then as needed for 24 months to maintain this level. The control group received placebo for 3 months and then weekly for 5 weeks at 6-month intervals for 24 months.

OUTCOMES

The primary end point was change in estimated glomerular filtration rate (eGFR) over time. A secondary end point was a 2-fold increase in baseline serum creatinine level or the requirement for renal replacement therapy.

MEASUREMENTS

Body lead burdens were assessed by EDTA mobilization tests and eGFR was calculated using the equation for Chinese patients with type 2 diabetes.

RESULTS

Mean baseline eGFRs in the treatment and control groups were similar. After 3 months of chelation therapy, the change in eGFR in the treatment group (+1.0 ± 4.8 mL/min/1.73 m(2)) differed significantly from that in the control group (-1.5 ± 4.8 mL/min/1.73 m(2); P = 0.04). In the subsequent 24-month intervention, the yearly rate of decrease in eGFR (5.6 ± 5.0 mL/min/1.73 m(2) per year) in the treatment group was slower than that (9.2 ± 3.6 mL/min/1.73 m(2) per year; P = 0.04) in the control group. 17 (68%) control-group patients and 9 (36%) treatment-group patients achieved the secondary end point.

LIMITATIONS

Small sample size, not double blind.

CONCLUSIONS

A 27-month course of EDTA chelation therapy retards the progression of diabetic nephropathy in type 2 diabetic patients with high-normal body lead burdens.