A Cross-sectional Study Measuring Vanadium and Chromium Levels in Paediatric Patients with CKD

Objectives: Although many secondary effects of high levels of vanadium (V) and chromium (Cr) overlap with symptoms seen in paediatric patients with chronic kidney disease (CKD), their plasma V and Cr levels are understudied.

Design: Ancillary cross-sectional study to a prospective, longitudinal, randomised controlled trial.

Setting: Children's Hospital of Western Ontario, London Health Sciences Centre, London, Ontario, Canada.

Participants: 36 children and adolescents 4-18 years of age with CKD.

Interventions: 1-6 trace element measurements per patient. Cystatin C (CysC) estimated glomerular filtration rate (eGFR) was calculated using the Filler formula. Plasma V and Cr levels were measured using high-resolution sector field inductively coupled mass spectrometry. Anthropomorphic data and blood parameters were collected from our electronic chart programme. Water Cr and V data were obtained from the Ontario Water (Stream) Quality Monitoring Network.

Primary And Secondary Outcome Measures: Primary outcomes: plasma Cr and V.

Secondary Outcomes: age, season, CysC, CysC eGFR, and Cr and V levels in environmental water.

Results: The median (IQR) eGFR was 51 mL/min/1.73 m (35, 75). The median V level was 0.12 µg/L (0.09, 0.18), which was significantly greater than the 97.5th percentile of the reference interval of 0.088 µg/L; 32 patients had at least one set of V levels above the published reference interval. The median Cr level was 0.43 µg/L (0.36, 0.54), which was also significantly greater than the established reference interval; 34 had at least one set of Cr levels above the published reference interval. V and Cr levels were moderately correlated. Only some patients had high environmental exposure.

Conclusions: Our study suggests that paediatric patients with CKD have elevated plasma levels of V and Cr. This may be the result of both environmental exposure and a low eGFR. It may be necessary to monitor V and Cr levels in patients with an eGFR <30 mL/min/1.73 m.

Trial Registration Number: NCT02126293; HC#172241.