Dietary evaluation of sodium intake in patients with chronic kidney disease.

Introduction: high sodium intake is a risk factor for diseases such as systemic arterial hypertension, stroke, left ventricular hypertrophy, and chronic kidney disease (CKD). Objective: to evaluate the correlation between estimated sodium intake by dietary intake and 24-hour urinary excretion in patients with non-dialysis CKD. Material and Methods: a cross-sectional study with 151 individuals. Demographic, socioeconomic, clinical and lifestyle data were evaluated. Sodium was dosed in 24-hour urine and estimated by 24-hour Food Recall (R24h). To evaluate the association between demographic, anthropometric, nutritional and laboratory variables with sodium excretion in 24-hour urine, variance analysis (ANOVA) or Kruskal-Wallis test were used. The correlation between 24-hour urinary sodium excretion and dietary sodium intake was performed by Spearman's correlation coefficient. Results: mean age was 60.8 ± 11.8 years, 51.7 % were women. Hypertensive patients, 88.9 %; diabetics, 45.0 %; and 39.1 % were in stage 3B of CKD. Median sodium excretion in 24-hour urine was 112.2 mmol/L and R24h intake was 833.8 mg/day. Individuals belonging to the highest tertile of sodium excretion (T3) presented lower PTH values, and those with lower tertile (T1), higher serum HDL-c levels (p < 0.05). There was no statistical correlation between dietary sodium intake and 24-hour urine excretion (p-value = 0.241). Conclusion: the non-correlation between sodium obtained by 24-hour urinary excretion and dietary intake demonstrates the fragility of the estimation of sodium excretion through the dietary survey.