title: Four to seven random casual urine specimens are sufficient to estimate 24-h urinary sodium/potassium ratio in individuals with high blood pressure.
abstract: This study was done to clarify the optimal number and type of casual urine specimens required to estimate urinary sodium/potassium (Na/K) ratio in individuals with high blood pressure. A total of 74 individuals with high blood pressure, 43 treated and 31 untreated, were recruited from the Japanese general population. Urinary sodium, potassium and Na/K ratio were measured in both casual urine samples and 7-day 24-h urine samples and then analyzed by correlation and Bland-Altman analyses. Mean Na/K ratio from random casual urine samples on four or more days strongly correlated with the Na/K ratio of 7-day 24-h urine (r=0.80-0.87), which was similar to the correlation between 1 and 2-day 24-h urine and 7-day 24-h urine (r=0.75-0.89). The agreement quality for Na/K ratio of seven random casual urine for estimating the Na/K ratio of 7-day 24-h urine was good (bias: -0.26, limits of agreements: -1.53-1.01), and it was similar to that of 2-day 24-h urine for estimating 7-day 24-h values (bias: 0.07, limits of agreement: -1.03 to 1.18). Stratified analyses comparing individuals using antihypertensive medication and individuals not using antihypertensive medication showed similar results. Correlations of the means of casual urine sodium or potassium concentrations with 7-day 24-h sodium or potassium excretions were relatively weaker than those for Na/K ratio. The mean Na/K ratio of 4-7 random casual urine specimens on different days provides a good substitute for 1-2-day 24-h urinary Na/K ratio for individuals with high blood pressure.
authors: Research and Development Department, OMRON HEALTHCARE Co., Ltd, Muko, Japan.|Department of Public Health, Shiga University of Medical Science, Otsu, Japan.
authors: T
authors: T
authors: Iwahori
authors: Department of Public Health, Shiga University of Medical Science, Otsu, Japan.|Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Otsu, Japan.
authors: H
authors: http://orcid.org/0000-0002-7742-4253
authors: H
authors: Ueshima
authors: Department of Public Health, Shiga University of Medical Science, Otsu, Japan.
authors: S
authors: S
authors: Torii
authors: Department of Public Health, Shiga University of Medical Science, Otsu, Japan.
authors: Y
authors: Y
authors: Saito
authors: Department of Public Health, Shiga University of Medical Science, Otsu, Japan.
authors: A
authors: A
authors: Fujiyoshi
authors: Department of Hygiene and Public Health, Teikyo University School of Medicine, Tokyo, Japan.
authors: T
authors: T
authors: Ohkubo
authors: Department of Public Health, Shiga University of Medical Science, Otsu, Japan.|Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Otsu, Japan.
authors: K
authors: K
authors: Miura
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006973:Hypertension / Q000652:urine*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000652:urine*; D012964:Sodium / Q000652:urine*; D059349:Urine Specimen Collection / Q000592:standards*
chemical_list: D012964:Sodium; D011188:Potassium