Prediction of 24-Hour Urinary Sodium Excretion Using a Single Spot Urine Samples in Moroccan Population

Abstract

Background: Excessive sodium intake is linked to high blood pressure. Estimating sodium intake is difficult. The 24-h urine collection is currently the recommended method for estimating intake but cumbersome for large population studies. Predictive model to estimate sodium intake based on single spot urine were developed, but showed inconsistency when used in extern populations. This study aims to develop a specific model for estimating sodium excretion over 24 hours for the Moroccan population. Methods: 371 participants in the urinary validation sub-study of the STEP-wise survey-Morocco 2017-2018 provided a valid 24-hour urine collection and spot urine specimens. Participant were randomly assigned to the training (n=183) and the validation data set (n=188). Results: A prediction model for 24-hour sodium excretion was developed. Adjusted R2 was 0.258. In the validation data set, correlation was 0.431 [95%CI; 0.258-0.580], and the adjusted R2 was 0.190. The Bland-Altman plot showed a nonsignificant small mean bias of -18 mg (95%CI, -213 to 177) in predicting 24-h urinary sodium excretion at the group level. At the individual level, limits of agreement were wide. Conclusion: This new model developed from a single spot urine could be used to predict the average 24-h sodium excretion of Moroccan adults.