Abstract
BACKGROUND/OBJECTIVES: Zinc supplementation induces metallothionein, leading to reduced serum copper levels. Conversely, serum copper concentrations tend to rise with the use of HIF-PH inhibitors. METHODS: To establish a safe level of zinc supplementation that avoids copper deficiency, serum copper and zinc concentrations measured every three months were retrospectively analyzed over five years in 50 patients undergoing hemodialysis. RESULTS: At the initiation of the study, the median (IQR) concentrations were 100 (84.25-109) µg/dL for serum copper and 60.5 (50.5-70) µg/dL for serum zinc. All participants without zinc supplementation exhibited zinc deficiency (<80 µg/dL). After three months, copper deficiency (<71 µg/dL) was observed when serum copper concentrations were <98.6 µg/dL for patients with HIF-PH inhibitors and <90.3 µg/dL for patients without them. Reduced zinc supplementation may be necessary when serum copper falls below 90 µg/dL. Zinc levels remained deficient because supplementation was limited due to concerns about copper deficiency. Lowering the target zinc level to around 80 µg/dL instead of the conventional 80-120 µg/dL may be safer. CONCLUSIONS: Regular monitoring of both copper and zinc levels, taking place at least every three months, is recommended to adjust zinc supplementation, especially in patients on HIF-PH inhibitors. Copper supplementation should also be considered alongside zinc supplementation to effectively treat hypozincemia.