High oxalate levels raised risk for sudden cardiac death by
Elevated concentrations of serum oxalate were associated with an increased risk for cardiovascular mortality, most notably from sudden cardiac death, according to a post-hoc analysis of the German Diabetes Dialysis Study.

The clinical significance of accumulating toxic terminal metabolites such as oxalate in kidney failure patients is not well understood.

This study aimed to evaluate serum oxalate concentrations and risk of all-cause mortality and cardiovascular events in a cohort of kidney failure patients requiring chronic dialysis, we performed a post-hoc analysis of the randomized German Diabetes Dialysis Study (4D Study); this study included 1255 European hemodialysis patients with diabetes followed up for a median of 4 years. The results obtained via Cox proportional hazards models were confirmed by competing risk regression and restricted cubic spline modeling in the 4D cohort and validated in a separate cohort of 104 US dialysis patients after a median follow-up of 2.5 years.

-- A total of 1108 patients had baseline oxalate measurements, with a median oxalate concentration of 42.4 µM. During follow-up, 548 died, including 139 (25.4%) from sudden cardiac death.

-- A total of 413 patients reached the primary composite cardiovascular endpoint (cardiac death, nonfatal myocardial infarction, and fatal or nonfatal stroke).

-- Patients in the highest oxalate quartile (more than 59.7 µM) had a 40% increased risk for cardiovascular events and a 62% increased risk of sudden cardiac death, compared with those in the lowest quartile (less than 29.6 µM).

-- The associations remained when accounting for competing risks and with oxalate as a continuous variable.

Conclusively, elevated serum oxalate is a novel risk factor for cardiovascular events and sudden cardiac death in dialysis patients. Further studies are warranted to test whether oxalate-lowering strategies improve cardiovascular mortality in dialysis patients.

Source: https://jasn.asnjournals.org/content/early/2021/07/19/ASN.2020121793