A New Approach Is Needed to Evaluate 24-Hour Urinary Sodium Excretion Using Spot Urines: A Validation Study in a
Yaguang Peng1, Ying Zhang2, Kun Li3
1National Center for Children's Health, China Key Laboratory of Pediatric Major Diseases Research Ministry of Education Beijing Children's Hospital Capital Medical University Beijing China.
Insights
Estimating children's daily sodium excretion using common formulas is inaccurate. These methods risk misclassifying individual sodium intake, hindering early cardiovascular disease prevention.
Area of Science:
- Pediatric Nutrition
- Cardiovascular Disease Prevention
- Biomarker Validation
Background:
- Accurate sodium intake assessment is crucial for pediatric cardiovascular disease prevention.
- Current methods for assessing children's sodium intake are often inaccurate, complex, or infeasible.
- Validating simple estimation formulas is needed for practical clinical application.
Purpose of the Study:
- To validate the accuracy of three common formulas (Kawasaki, INTERSALT, Tanaka) for estimating 24-hour urinary sodium excretion (UNaV) in children.
- To compare the performance of these formulas against measured 24-hour UNaV.
Main Methods:
- A hospital-based cohort of 129 Chinese children aged 5-16 years participated.
- 24-hour urine samples were collected for direct measurement of UNaV.
- Estimated UNaV using Kawasaki, INTERSALT, and Tanaka formulas was compared to measured values.
Main Results:
- Mean measured UNaV was 2694.9 mg/day.
- Mean differences between estimated and measured UNaV were substantial for Kawasaki (2367.6 mg/day) and Tanaka (258.8 mg/day), but smaller for INTERSALT (26.4 mg/day).
- High proportions of relative differences (>40%) and individual misclassification rates were observed for all three formulas (Kawasaki: 79.8%, 73.1%; INTERSALT: 34.9%, 69.0%; Tanaka: 38.5%, 62.4%).
Conclusions:
- The Kawasaki, INTERSALT, and Tanaka formulas are not reliable for estimating individual 24-hour urinary sodium excretion in children.
- The high risk of misclassification using these spot urine-based formulas limits their utility in clinical practice.
- Further research is needed to develop accurate and feasible methods for assessing pediatric sodium intake.
Abstract:
Background Accurate assessments of sodium intake in children are important for the early prevention of cardiovascular disease. There is currently no accurate simple and feasible sodium intake approach for children. This study intends to validate the accuracy of 24-hour urinary sodium excretion (UNaV) estimation in children using 3 common formulas: the Kawasaki, INTERSALT (International Cooperative Study on Salt, Other Factors, and Blood Pressure), and Tanaka formulas. Methods and Results A hospital-based child population in China was enrolled in the study and completed 24-hour urine sample collection. Concentrations of sodium, potassium, and creatinine in 24-hour urine and spot urine samples were measured. Mean difference as well as absolute and relative differences and misclassification between estimation and measurement of UNaV with 3 commonly used formulas were compared and analyzed. A total of 129 participants aged 5 to 16 years were eligible for analysis. Mean measured UNaV was 2694.9 mg/day. Mean differences between estimated and measured UNaV by the Kawasaki, INTERSALT, and Tanaka formulas were 2367.6, 26.4, and 258.8 mg/day, respectively. Proportions of relative differences of over 40% for the Kawasaki, INTERSALT, and Tanaka formulas were 79.8%, 34.9%, and 38.5%, respectively. Misclassification rates were 73.1% for Kawasaki, 69.0% for INTERSALT, and 62.4% for Tanaka at the individual level. Conclusions The results from our study do not support estimation of UNaV for children by the Kawasaki, INTERSALT, and Tanaka formulas using single spot urine samples because of the potential risk for misclassification at the individual level.
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