To the Editor Mills and colleagues1 found that among patients with CKD, higher urinary sodium excretion was associated with increased risk of CVD. Analyses were adjusted for important covariates for CVD. In all the models, a significantly increased risk of CVD was documented in patients with the highest quartile of sodium excretion.
One of the variables that was not included in the statistical analysis was urinary protein excretion. In Table 1 in the article, where the characteristics of patients were described, urinary protein excretion was correlated with urinary sodium excretion. This correlation has been described previously by the same group in the same cohort of patients.2
Almirall J. Sodium Excretion, Cardiovascular Disease, and Chronic Kidney Disease. JAMA. 2016;316(10):1112. doi:10.1001/jama.2016.11553