Serum oxalate concentration is associated with coronary artery calcification and cardiovascular events in Japanese dialysis patients

Coronary artery calcification (CAC) is associated with cardiovascular disease (CVD). CAC might contain calcium oxalate, and a high serum oxalate (S(Ox)) concentration is associated with cardiovascular mortality in dialysis patients. We assessed the associations between S(Ox) and CAC or CVD events in Japanese hemodialysis patients. This cross-sectional and retrospective cohort study was done in 2011. Seventy-seven hemodialysis patients’ Agatston CAC score was measured, and serum samples were collected. S(Ox) concentrations were measured in 2021 by using frozen samples. Also, new-onset CVD events in 2011–2021 were retrospectively recorded. The association between S(Ox) concentration and CAC score ≥ 1000, and new-onset CVD events were examined. Median S(Ox) concentration and CAC score were 266.9 (229.5–318.5) µmol/L and 912.5 (123.7–2944), respectively. CAC score ≥ 1000 was associated with S(Ox) [adjusted odds ratio (OR) 1.01, 95% confidence interval (CI), 1.00–1.02]. The number of new-onset CVD events was significantly higher in patients with S(Ox) ≥ median value [hazard ratio (HR) 2.71, 95% CI 1.26–6.16]. By Cox proportional hazard models, new-onset CVD events was associated with S(Ox) ≥ median value (adjusted HR 2.10, 95% CI 0.90–4.91). S(Ox) was associated with CAC score ≥ 1000 and new-onset CVD events in Japanese hemodialysis patients.