Association Between Blood Cobalt Levels and Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis: A Multicenter Observational Study.

RATIONALE &

OBJECTIVE

Prior studies have suggested that increased cobalt ion concentrations in circulation provoke inflammation in endothelial cells, disrupting vascular function. In patients undergoing maintenance hemodialysis (MHD), elevated cobalt may result from various factors. Given the critical role of arteriovenous fistulas (AVFs) in the survival of MHD patients, we aimed to investigate the relationship between cobalt levels and AVF dysfunction.

STUDY

DESIGN

Multicenter, observational cohort study.

SETTING & STUDY POPULATIONS: A total of 518 patients undergoing maintenance hemodialysis at 3 medical centers.

EXPOSURES: Blood samples were collected before dialysis, and whole-blood cobalt levels were determined using inductively coupled plasma mass spectrometry.

OUTCOMES: Blood cobalt concentrations were measured at baseline. Participants were monitored for AVF dysfunction, defined by a blood flow reduction to ≤200 mL/min during dialysis, and followed up to 2 years.

ANALYTICAL APPROACH: Patients were divided into groups based on the occurrence of AVF dysfunction and analyzed using multivariable Cox regression, Kaplan-Meier curves, log-rank tests, restricted cubic spline analysis, and stratified analysis.

RESULTS

Of the 518 patients, 126 (24.3%) experienced AVF dysfunction within a median 16-month follow-up. Patients with AVF dysfunction exhibited significantly higher blood cobalt concentrations than did those without AVF dysfunction. The highest AVF dysfunction rate was observed in patients in the upper cobalt quartile (P < 0.001). Multivariable analysis indicated a 2.90-fold increased risk of AVF dysfunction in patients in the highest cobalt level quartile (P < 0.001). No significant interactions were observed in the stratified analyses (P > 0.05).

LIMITATIONS: We only assessed the baseline cobalt levels at enrollment and did not perform serial measurements; we could not determine whether factors influencing trace element intake or absorption (eg, dietary habits or lifestyle) might have introduced temporal fluctuations in cobalt levels during follow-up, potentially influencing the results.

CONCLUSIONS

Elevated blood cobalt levels were independently associated with an increased risk of AVF dysfunction in patients undergoing MHD. Further research on cobalt metabolism and its effects on AVF functionality to guide clinical interventions is required.