Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

The relationship between repeated measurement of casual and 24-h urinary sodium-to-potassium ratio in patients with chronic kidney disease

Journal of Human Hypertension volume 33, pages 286–297 (2019)Cite this article

Subjects

Abstract

This study aimed to clarify the relationship between repeated measurements of casual (spot) and 24-h urinary sodium-to-potassium (Na/K) ratios in patients with chronic kidney disease (CKD). A total of 61 inpatients with CKD, 31 in stage 1–3 (eGFR [estimated glomerular filtration rate] ≥ 30 ml/min/1.73 m2) and 30 in stage 4–5 (eGFR < 30 ml/min/1.73 m2), aged 20–85 consuming a low-sodium diet (NaCl [sodium chloride] 6 g/day) were recruited. Urinary Na, K, and Na/K ratios were measured in both casual urine samples and 2-day, 24 h urine samples, and then analyzed by correlation and Bland–Altman analyses. Mean 24-h urine Na/K ratio was higher in participants in stage 4–5 (5.1) than in participants in stage 1–3 (4.1) CKD. Casual urine Na/K ratio was strongly correlated with 2-day, 24-h urine Na/K ratio by sampling 4 casual urine specimens every morning and evening in participants in stage 1–3 (r = 0.69–0.78), but not in stage 4–5 (r = 0.12–0.19). The bias for mean Na/K ratio between 2-day, 24-h urine, and the 4 casual urine sampling ranged from −0.86 to 0.16 in participants in stage 1–3, and the quality of agreement for the mean of this casual urine sampling was similar to that of sampling 8 casual urine samples for estimating 2-day, 24-h values. Methods using repeated casual urine Na/K ratios may provide a reasonable estimation of 24-h urine Na/K ratio in normotensive and hypertensive as well as individuals with stage 1–3, but not stage 4–5 CKD.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1

Similar content being viewed by others

References

  1. Levey AS, Coresh J, Balk E, Kausz AT, Levin A, Steffes MW, et al. National Kidney Foundation. National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Ann Intern Med. 2003;139(2):137–47. [Erratum in: Ann Intern Med. 2003 Oct 7;139:605]

    Article  PubMed  Google Scholar 

  2. K/DOQI clinical practice guidelines on hypertension and antihypertensive agents in chronic kidney disease. Am J Kidney Dis. 2004;43(5 Suppl 1):S1–290.

  3. Brown IJ, Tzoulaki I, Candeias V, Elliott P. Salt intakes around the world: implications for public health. Int J Epidemiol. 2009 Jun;38:791–813.

    Article  PubMed  Google Scholar 

  4. Drewnowski A, Rehm CD, Maillot M, Mendoza A, Monsivais P. The feasibility of meeting the WHO guidelines for sodium and potassium: a cross-national comparison study. BMJ Open. 2015;5:e006625.

    Article  PubMed  PubMed Central  Google Scholar 

  5. Guideline: sodium intake for adults and children. Geneva: World Health Organization (WHO); 2012. P.

  6. Guideline: potassium intake for adults and children. Geneva: World Health Organization (WHO); 2012. P.

  7. Whelton PK, Appel LJ, Sacco RL, Anderson CA, Antman EM, Campbell N, et al. Sodium, blood pressure, and cardiovascular disease: further evidence supporting the American Heart Association sodium reduction recommendations. Circulation. 2012;126:2880–9.

    Article  CAS  PubMed  Google Scholar 

  8. Hunter D Biochemical indicators of dietary intake. In: Willet W., Nutritional Epidemiology, Second Edition. Oxford University Press: New York, NY, USA, 1998, p. 174–243.

  9. Pietinen PI, Findley TW, Clausen JD, Finnerty FA, Altschul AM. Studies in community nutrition: estimation of sodium output. Prev Med. 1976;5:400–7.

    Article  CAS  PubMed  Google Scholar 

  10. Liu K, Stamler J. Assessment of sodium intake in epidemiological studies on blood pressure. Ann Clin Res. 1984;16(Suppl 43):49–54.

    PubMed  Google Scholar 

  11. Cogswell ME, Mugavero K, Bowman BA, Frieden TR. Dietary sodium and cardiovascular disease risk—measurement matters. N Engl J Med. 2016;375:580–6.

    Article  PubMed  PubMed Central  Google Scholar 

  12. Dennis B, Stamler J, Buzzard M, Conway R, Elliott P, Moag-Stahlberg A, et al. INTERMAP Research Group. INTERMAP: the dietary data—process and quality control. J Hum Hypertens. 2003;17:609–22.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Cobb LK, Anderson CA, Elliott P, Hu FB, Liu K, Neaton JD, et al. American Heart Association Council on Lifestyle and Metabolic Health. Methodological issues in cohort studies that relate sodium intake to cardiovascular disease outcomes: a science advisory from the American Heart Association. Circulation. 2014;129:1173–86.

    Article  CAS  PubMed  Google Scholar 

  14. Lerchl K, Rakova N, Dahlmann A, Rauh M, Goller U, Basner M, et al. Agreement between 24-hour salt ingestion and sodium excretion in a controlled environment. Hypertension. 2015;66:850–7.

    Article  CAS  PubMed  Google Scholar 

  15. Kawasaki T, Itoh K, Uezono K, Sasaki H. A simple method for estimating 24 h urinary sodium and potassium excretion from second morning voiding urine specimen in adults. Clin Exp Pharmacol Physiol. 1993;20:7–14.

    Article  CAS  PubMed  Google Scholar 

  16. Tanaka T, Okamura T, Miura K, Kadowaki T, Ueshima H, Nakagawa H, et al. A simple method to estimate populational 24-h urinary sodium and potassium excretion using a casual urine specimen. J Hum Hypertens. 2002;16:97–103.

    Article  CAS  PubMed  Google Scholar 

  17. Brown IJ, Dyer AR, Chan Q, Cogswell ME, Ueshima H, Stamler J, et al. INTERSALT Co-Operative Research Group. Estimating 24-hour urinary sodium excretion from casual urinary sodium concentrations in Western populations: the INTERSALT study. Am J Epidemiol. 2013;177:1180–92.

    Article  PubMed  PubMed Central  Google Scholar 

  18. Polonia J, Lobo MF, Martins L, Pinto F, Nazare J. Estimation of populational 24-h urinary sodium and potassium excretion from spot urine samples: evaluation of four formulas in a large national representative population. J Hypertens. 2017;35:477–86.

    Article  CAS  PubMed  Google Scholar 

  19. Huang L, Crino M, Wu JH, Woodward M, Barzi F, Land MA, et al. Mean population salt intake estimated from 24-h urine samples and spot urine samples: a systematic review and meta-analysis. Int J Epidemiol. 2016;45:239–50.

    Article  PubMed  Google Scholar 

  20. Iwahori T, Miura K, Ueshima H. Time to consider use of the sodium-to-potassium ratio for practical sodium reduction and potassium increases. Nutrients. 2017;9:E700.

    Article  PubMed  Google Scholar 

  21. INTERSALT: an international study of electrolyte excretion and blood pressure. Results for 24-h urinary sodium and potassium excretion. Br Med J. 1988;297:319–28.

  22. Stamler J, Rose G, Stamler R, Elliott P, Dyer A, Marmot M. INTERSALT study findings. Public health and medical care implications. Hypertension. 1989;14:570–7.

    Article  CAS  PubMed  Google Scholar 

  23. Tzoulaki I, Patel CJ, Okamura T, Chan Q, Brown IJ, Miura K, et al. A nutrient-wide association study on blood pressure. Circulation. 2012;126:2456–64.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Perez V, Chang ET. Sodium-to-potassium ratio and blood pressure, hypertension, and related factors. Adv Nutr. 2014;5:712–41.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Cook NR, Obarzanek E, Cutler JA, Buring JE, Rexrode KM, Kumanyika SK, et al. Trials of Hypertension Prevention Collaborative Research Group. Joint effects of sodium and potassium intake on subsequent cardiovascular disease: the Trials of Hypertension Prevention follow-up study. Arch Intern Med. 2009;169:32–40.

    Article  PubMed  PubMed Central  Google Scholar 

  26. Cook NR, Appel LJ, Whelton PK. Sodium intake and all-cause mortality over 20 years in the Trials of Hypertension Prevention. J Am Coll Cardiol. 2016;68:1609–17.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Cook NR, Cutler JA, Obarzanek E, Buring JE, Rexrode KM, Kumanyika SK, et al. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP). Br Med J. 2007;334:885–8. Epub 2007 Apr 20

    Article  Google Scholar 

  28. Kieneker LM, Bakker SJ, de Boer RA, Navis GJ, Gansevoort RT, Joosten MM. Low potassium excretion but not high sodium excretion is associated with increased risk of developing chronic kidney disease. Kidney Int. 2016;90:888–96.

    Article  CAS  PubMed  Google Scholar 

  29. Iwahori T, Ueshima H, Ohgami N, Yamashita H, Miyagawa N, Kondo K, et al. Effectiveness of a self-monitoring device for urinary sodium/potassium ratio on dietary improvement in free-living adults: a randomized controlled trial. J Epidemiol. 2018;28:41–47.

    Article  PubMed  PubMed Central  Google Scholar 

  30. Iwahori T, Miura K, Ueshima H, Chan Q, Dyer AR, Elliott P, et al. INTERSALT Research Group. Estimating 24-hour urinary sodium/potassium ratio from casual (“spot”) urinary sodium/potassium ratio: The INTERSALT Study. Int J Epidemiol. 2017;46:1564–72.

    PubMed  Google Scholar 

  31. Iwahori T, Ueshima H, Miyagawa N, Ohgami N, Yamashita H, Ohkubo T, et al. Six random samples of casual urine on different days are sufficient to estimate daily sodium/potassium ratio as compared to 7-day 24-h urine collections. Hypertens Res. 2014;37:765–71.

    Article  CAS  PubMed  Google Scholar 

  32. Iwahori T, Ueshima H, Torii S, Saito Y, Fujiyoshi A, Ohkubo T, et al. Four to seven random casual urine specimens are sufficient to estimate 24-hr urinary sodium/potassium ratio in individuals with high blood pressure. J Hum Hypertens. 2016;30:328–34.

    Article  CAS  PubMed  Google Scholar 

  33. Matsuo S, Imai E, Horio M, Yasuda Y, Tomita K, Nitta K, et al. Collaborators developing the Japanese equation for estimated GFR. Revised equations for estimated GFR from serum creatinine in Japan. Am J Kidney Dis. 2009;53:982–92.

    Article  CAS  PubMed  Google Scholar 

  34. Bland J, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1:307–10.

    Article  CAS  PubMed  Google Scholar 

  35. Iwahori T, Ueshima H, Torii S, Saito Y, Kondo K, Tanaka-Mizuno S, et al. Diurnal variation of urinary sodium-to-potassium ratio in free-living Japanese individuals. Hypertens Res. 2017;40:658–64.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Koeppen BM, Stanton BA. Renal transport mechanisms: NaCl and water reabsorption along the nephron. In: Koeppen BM, Stanton BA, Renal Physiology, Fifth Edition. Elsevier Inc.: Amsterdam, Netherlands, 2013. p. 45–71.

    Chapter  Google Scholar 

  37. Dhondup T, Qian Q. Electrolyte and acid-base disorders in chronic kidney disease and end-stage kidney failure. Blood Purif. 2017;43:179–88.

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgments

This study was conducted by Okayama University hospital in cooperation with the Department of Public Health, Shiga University of Medical Science. HAU and TI contributed to the design of the study. HAU, YO, and AK participated in data collection. HAU, TI, and YO participated in data analysis and contributed to manuscript drafting. All authors participated in critical revision of the manuscript. All authors approved the final version of the manuscript for submission. The authors thank Mrs. Debra L. Rateri (University of Kentucky) for skillful English editing.

Funding

This work was supported by a scientific research grants from Japanese Study Group for Physiology and Management of Blood Pressure.

Author information

Authors and Affiliations

  1. Department of Nephrology, Rheumatology, Endocrinology and Metabolism, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan

    Yuka Okuyama, Haruhito A. Uchida, Ayako Kato, Hidemi Takeuchi, Yuki Kakio, Ryoko Umebayashi, Masashi Kitagawa & Jun Wada

  2. Department of Chronic Kidney Disease and Cardiovascular Disease, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan

    Haruhito A. Uchida

  3. Department of Public Health, Shiga University of Medical Science, Otsu, Japan

    Toshiyuki Iwahori, Katsuyuki Miura & Hirotsugu Ueshima

  4. Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan

    Toshiyuki Iwahori

  5. Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Otsu, Japan

    Hiroyoshi Segawa, Katsuyuki Miura & Hirotsugu Ueshima

  6. Department of Human Resource Development of Dialysis Therapy for Kidney Disease, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan

    Hitoshi Sugiyama

Authors
  1. Yuka Okuyama
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Haruhito A. Uchida
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Toshiyuki Iwahori
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Hiroyoshi Segawa
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Ayako Kato
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Hidemi Takeuchi
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Yuki Kakio
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Ryoko Umebayashi
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Masashi Kitagawa
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Hitoshi Sugiyama
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Katsuyuki Miura
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Hirotsugu Ueshima
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Jun Wada
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Haruhito A. Uchida.

Ethics declarations

Conflict of interest

Dr. Haruhito A. Uchida belongs to the Department of Chronic Kidney Disease and Cardiovascular Disease which is endowed by Chugai pharmaceutical, MSD, Boehringer Ingelheim, and Kawanishi Holdings. Dr. Toshiyuki Iwahori was an employee of OMRON HEALTHCARE Co., Ltd. until March, 2018. Dr. Hirotsugu Ueshima served as a consultant for this project. Dr. Katsuyuki Miura received a research grant from OMRON HEALTHCARE Co., Ltd.

Electronic supplementary material

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Okuyama, Y., Uchida, H.A., Iwahori, T. et al. The relationship between repeated measurement of casual and 24-h urinary sodium-to-potassium ratio in patients with chronic kidney disease. J Hum Hypertens 33, 286–297 (2019). https://doi.org/10.1038/s41371-018-0127-1

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41371-018-0127-1

This article is cited by

Search

Advanced search

Quick links