Author Reply to Comment on "Assessment of Plasma Oxalate Concentration in Patients With CKD" by Oka et al.

The Author Replies: We thank Oka et al. for the precise summary of our study “Assessment of plasma oxalate concentration in patients with CKD” and their excellent suggestions for future investigations. As proposed, we added a regression line to the scatter plot that illustrates the correlation between estimated glomerular filtration rate and plasma oxalate concentration (Figure 1) with the correlation coefficient r being −0.22 (Spearman correlation; P < 0.001).

Figure 1

Plasma oxalate concentrations (POx) and corresponding estimated glomerular filtration rate (eGFR) in 1826 patients with chronic kidney disease (German Chronic Kidney Disease = GCKD study population). POx were measured in 1826 patients of the GCKD study and plotted against the corresponding calculated eGFR. The y-axis is log-scaled. The red dashed line represents the regression line (Spearman correlation: r = −0.22, P < 0.001).

The pathophysiological role of oxalate in chronic kidney disease and its potential impact on clinical outcomes have not been addressed by our study. We agree with Oka et al. that it is worth widening our view on the role of plasma oxalate concentrations. Therefore, further analyses will not only focus on renal endpoints such as progression of kidney disease or graft survival, but also on cardiovascular outcomes.