24-h Urine Collection: A Relevant Tool in CKD Nutrition Evaluation

Abstract

Dietary management is a cornerstone of Chronic Kidney Disease (CKD) monitoring, and dietary surveys often difficult to perform. We studied in a CKD patient cohort with two years follow-up, whether validated 24-h urine ionogram would be a relevant tool for diet evaluation and compliance. We included 404 non-dialysis CKD patients, with three evaluations, including repeated measurements of fractional renal creatinine clearance and 24-h urine collection. Completeness of the 24-h urine collection, assessed by daily urine creatinine excretion extrapolated from fractional creatinine clearance, was 64.6%, 75.5%, and 78.2% at the first, second, and third visits, respectively. One hundred sixty-eight patients (41.6%) had three complete collections, with a measured glomerular filtration of 42.3 mL/min/1.73 m2 at baseline and prevalence of anemia and secondary hyperparathyroidism of 13.9% and 26.2%, respectively, increasing during follow-up to 15% and 31.5% (p < 0.001 and p < 0.001). The urine analysis showed at baseline a urine volume of above 2 L/day, and estimated sodium and protein intake within targets in 51.6% and 40.3% of cases, which improved during follow-up only for protein (to 45.9%, p < 0.0001). Our data suggest that a 24-h urine ionogram is an interesting, reliable tool in CKD patients for dietary monitoring to achieve target recommendation noteworthy salt and protein intake.

Estimation of dietary intake of sodium, potassium, phosphorus and protein in healthy Indian population and patients with chronic kidney disease

“…A total of 4 aliquots of 2 mL were stored at -80°C, out of which one was given to the biochemistry laboratory for analysis. Estimation of dietary intake using 24-h urinary excretion has been considered a reliable tool provided the compliance of 24-h urine collection has been validated which we have done carefully ( 22 ).…”

“…The dietary protein intake is best estimated by measuring the urea nitrogen appearance rate, which requires a 24-h urine collection (22). Similarly, the estimation of the 24-h urinary sodium excretion is the gold standard for estimating salt intake (23)(24)(25)(26), and dietary potassium intake is correlated with the 24-h urinary excretion of potassium (27,28).…”

Editorial: Nutrition Management for Chronic Kidney Disease

“…Estimating nutritional intake and dietary monitoring is of utmost importance for providing proper nutritional counselling. Abdel-Nabey et al, on behalf of the French NephroTest Study Group, studied over 400 CKD patients and concluded that twenty-four-hour urine collections are feasible and represent a reliable tool for dietary monitoring and could be used in making individual recommendations for salt and protein intake [ 8 ]. Expanding on the topic of assessing nutritional parameters, Ginos and Olde-Engberink reviewed evidence on sodium and potassium intake methods based on twenty-four-hour urine collections or spot urine estimations (including spot Na/K ratio) in the general population and CKD patients, exploring suggestions that may improve test accuracy without increasing the associated burden for the patients [ 9 ].…”