Estimation of populational 24-h urinary sodium and potassium excretion from spot urine samples: evaluation of four formulas in a large national representative population
Polonia et al. evaluate the validity of several 24-h sodium and potassium excretion estimating formulae. These formulae were developed to estimate 24-h urine excretion (hence daily intake) of sodium and/or potassium from a spot urine sample [2–5], and their validation is indeed crucial as they have been used in large population studies to establish the link between sodium intake and cardiovascular events [6,7]. However, this study carries major methodological flaws which limit its interpretation.