Quantification of sodium ingestion in chronic kidney disease

• Grant number: 20/15766-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): April 01, 2021
• Effective date (End): March 31, 2023
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Luis Cuadrado Martin
• Grantee: Ryan Nunes Yoshio Yoshihara
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Rationale. After the industrial revolution, the population had greater access to salt, which led to an increase in consumption to levels above the recommended. This excessive sodium intake increases the risk of chronic diseases, namely: high blood pressure, cardiovascular disease and chronic kidney disease. Chronic kidney disease has become a pandemic in recent years, with an alarming increase in the number of patients requiring dialysis. With the reduction of sodium intake, the need for chronic dialysis procedures could be reduced with a major impact on public health. For the proper management of sodium intake recommendations, it is important to measure its consumption. The gold standard for measuring sodium intake is urinary sodium, but it does require urine collection and laboratory costs. To quantify it through food intake surveys, the following is used: 24-hour recall, food record and food frequency questionnaire, however, the accuracy of such methods has been little studied in relation to the gold standard. This question has not been investigated with chronic kidney disease patients. Therefore, the objective of the present study is to evaluate, in patients with chronic non-dialysis kidney disease, different methods for sodium intake in relation to the gold standard. Patients and methods. Prospective observational work will be carried out, in which the quantification of sodium intake will be carried out by assessing the food consumption of patients with CKD and compared to urinary sodium in 24 hours and the urinary sodium / creatininuria ratio. The dosages of urinary sodium and creatininuria are already part of the routine of care for patients with chronic kidney disease, not requiring new dosages. The calculated sample size will be 50 patients. This number results from the ability to detect a correlation coefficient of 0.4 with an alpha error of 0.05 and beta error of 0.2, plus 15 patients asa safety margin. Linear regression with Person's correlation coefficient between the different sodium quantification methods and the gold standard will be used. The average differences will be plotted on a Bland-Altman diagram. ROC curves will be drawn considering the sodium intake of 100 mEq / 24h as the desired outcome. Cutoff points will be established by the Youden index and for this Sensitivity, specificity, positive, negative predictive value, accuracy, positive and negative likelihood ratio will be calculated. The p value of 0.05 will be considered statistically significant.