To determine the relationship of urate excretion to body lead stores in patients with chronic renal disease without previous lead exposure.
We compared 40 male subjects in 3 groups, on the basis of their serum creatinine and histories of gout, with serum urate, creatinine clearance, urate clearance, daily urate excretion, fractional urate excretion, and body lead stores. Group 1 consisted of 10 patients with normal serum creatinine levels and no evidence of gout. Group 2 contained 10 men with gout and abnormal serum creatinine levels. Group 3 included 20 subjects with abnormal serum creatinine levels and no evidence of gout. All patients received EDTA mobilization tests and 72 h urine collections. The total amount of lead excreted over 72 h was estimated as the body lead stores. An ANOVA test with Fisher pairwise least significant difference, correlation coefficients, and multiple linear regression test were used to measure any statistical significance among these variables. A p value < 0.05 was considered significant.
Lead stores and serum urate were significantly higher in gouty patients with renal insufficiency than those of other groups, but the urate excretion of gouty patients was not relatively increased. Not only was there a significant correlation between creatinine clearance and urate excretion, but body lead stores also appeared to be negatively related to urate excretion in our patients, even though body lead stores in these subjects were within the normal range.
Our findings suggest that lead may play a role in gouty patients with impaired renal function and chronic low level environmental lead exposure may subtly affect urate excretion in patients with chronic renal disease.