Increased 24 h Urinary Cadmium Excretion Following Intravenous Ca-DTPA: A Retrospective Paired Analysis

Cadmium is a widespread environmental toxicant associated particularly with renal tubular injury and skeletal disease. Human evidence regarding chelation-enhanced cadmium elimination is limited. This retrospective paired analysis evaluated changes in 24 h urinary cadmium excretion following intravenous calcium diethylenetriaminepentaacetate (Ca-DTPA) in 60 patients treated primarily for suspected gadolinium-related conditions. The cohort included 30 women and 30 men, aged 21-79 years (mean, 49 years). Mean urinary cadmium excretion increased from 0.32 to 1.31 µg/24 h following Ca-DTPA administration, corresponding to a mean paired increase of 0.99 µg/24 h (95% CI, 0.75-1.23 µg/24 h). The ratio of the post-treatment to pretreatment group means was 4.09, while the median individual post/pre ratio was approximately 3.7 (IQR, 2.4-5.8; range, 1.2-9.5). All 60 participants showed increased urinary cadmium excretion (Wilcoxon signed-rank p < 0.001; two-sided exact sign-test p = 1.73 × 10^-18). These findings demonstrate increased urinary cadmium excretion following Ca-DTPA under the conditions studied, but do not establish a clinically meaningful reduction in total-body cadmium burden, treatment safety, or clinical benefit.