Mobilizable lead in patients with chronic renal failure

Blood lead (Pb) and urinary Pb before and after i.v. infusion of 1 g of Na2Ca EDTA were determined (atomic absorption) in 46 control subjects and 91 patients with various stages of renal failure (median serum creatinine 2.5 mg dl-1). Under baseline conditions, patients with renal failure had higher blood Pb levels (112 ng ml-1, range 44-272 vs. 76; 36-187 in controls; P less than 0.001) and lower urinary Pb (16.2 nmol 24 h-1 1.73 m-2, 4.86-66.8 vs. 33; 11-91 in controls; P = 0.001). The increment in urinary Pb after EDTA infusion (mobilizable Pb) was higher (795 nmol 4 days-1 1.73 m-2, range 155-5611 vs. 307; 131-1587 in controls; P = 0.001). In 12 patients with renal failure (13%) mobilizable Pb was above the highest value in controls. Mobilizable urinary Pb correlated (r = 0.68) significantly (P = 0.001) with blood Pb, but only marginally with serum creatinine (r = 0.32; P less than 0.007). Mobilizable Pb was higher in patients with renal failure and a history of smoking or occupational Pb exposure and tended to be higher in patients with alcoholism. Ten of 91 patients had gout; increased mobilizable Pb was present in three of the 10. The data confirm relatively high prevalence of elevated body Pb burden in European patients with chronic renal failure. The question is unresolved whether Pb plays a role in the progression of renal failure.