High Blood Cu/Zn Ratio is Associated with Nutritional Risk in Patients Undergoing Maintenance Hemodialysis

Patients undergoing maintenance hemodialysis (MHD) are at risk of an imbalance of copper and zinc homeostasis. We hypothesized that there is an association between the blood copper-zinc (Cu/Zn) ratio and nutritional status in these patients. For this cross-sectional study, blood samples were collected from patients undergoing MHD at Guangzhou Red Cross Hospital in September 2019. Zinc and copper levels were measured using inductively coupled plasma mass spectrometry. The seven-point subjective global assessment (SGA), nutritional risk screening 2002 (NRS2002), and geriatric nutritional risk index (GNRI) were used to evaluate the overall nutritional status. We enrolled 144 MHD patients (men:women = 78:66), with an average age of 64.33 ± 13.39 years and a median dialysis vintage of 33.50 (16.25-57.50) months. Patients with a higher blood Cu/Zn ratio had lower levels of hemoglobin, blood zinc, serum prealbumin, albumin, and creatinine as well as low SGA and GNRI scores, but higher modified Charlson comorbidity index score, serum C-reactive protein level, interleukin-6 level, blood copper level, and NRS2002 score (all p < 0.05). After adjustment for confounding factors in multivariable models, a high blood Cu/Zn ratio was independently associated with nutritional risk defined by all nutritional parameters (SGA, NRS2002, and GNRI). Prospective studies with larger sample sizes are warranted to confirm these results.