Skip to main content
SpringerLink
Log in

Validation of the equations for estimating daily sodium excretion from spot urine in patients with chronic kidney disease

  • Original Article
  • Published:
Clinical and Experimental Nephrology Aims and scope Submit manuscript

An Erratum to this article was published on 23 March 2013

Abstract

Background

Measuring sodium excretion in a 24-h urine collection is the most reliable method of estimating salt intake, but it is not applicable to all patients. As an alternative, equations for estimating Na excretion from Japanese by a spot urine sample were created, but they have not been validated in patients with chronic kidney disease (CKD), which are frequently associated with nocturia and medication.

Methods

We enrolled 136 patients with CKD and collected both 24-h urine and the first morning urine. Na excretion was estimated from the first morning urine by Kawasaki’s equation, which was originally used for the second morning urine, and Tanaka’s equation, which is applied for spot urine samples taken at any time from 9 am to 7 pm. We evaluated the two equations for bias, RMSE and accuracy within 30 and 50% of the measured Na excretion.

Results

Bias, RMSE and accuracy within 30% of the estimated Na excretion were 48 ± 69 and 2 ± 69 mmol/day, 84 and 69 mmol/day, and 35 and 49% using Kawasaki’s equation and Tanaka’s equation, respectively. Na excretion in the first morning urine was accurately estimated by Tanaka’s equation, but it was overestimated by Kawasaki’s equation. Nocturia and medication such as diuretics and ACE inhibitor or angiotensin receptor blocker did not affect the accuracy with which Na excretion was estimated by Tanaka’s equation substantially.

Conclusion

Tanaka’s equation for estimating Na excretion from the first morning urine in patients with CKD is accurate enough for use in clinical practice.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

References

  1. Strazzullo P, D’Elia L, Kandala NB, Cappuccio FP. Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. BMJ. 2009;339:b4567.

    Article  PubMed  Google Scholar 

  2. Cook NR, Cutler JA, Obarzanek E, Buring JE, Rexrode KM, Kumanyika SK, Appel LJ, Whelton PK. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP). BMJ. 2007;334(7599):885–8.

    Article  PubMed  Google Scholar 

  3. Intersalt Cooperative Research Group. Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. BMJ. 1988;297(6644):319–28.

    Google Scholar 

  4. Hooper L, Bartlett C, Davey Smith G, Ebrahim S. Reduced dietary salt for prevention of cardiovascular disease. Cochrane Database Syst Rev. 2003;3:CD003656.

    Google Scholar 

  5. Bibbins-Domingo K, Chertow GM, Coxson PG, Moran A, Lightwood JM, Pletcher MJ, Goldman L. Projected effect of dietary salt reductions on future cardiovascular disease. N Engl J Med. 2010;362(7):590–9.

    Article  PubMed  CAS  Google Scholar 

  6. The Japanese Society of Hypertension. Guidelines (JSH 2009). Chapter 4: lifestyle modifications. Hypertens Res. 2009;32:29–32.

    Google Scholar 

  7. Kawano Y, Tsuchihashi T, Matsuura H, Ando K, Fujita T, Ueshima H. Report of the Working Group for Dietary Salt Reduction of the Japanese Society of Hypertension. 2. Assessment of salt intake in the management of hypertension. Hypertens Res. 2007;30(10):887–93.

    Google Scholar 

  8. Kamata K, Tochikubo O. Estimation of 24-h urinary sodium excretion using lean body mass and overnight urine collected by a pipe-sampling method. J Hypertens. 2002;20(11):2191–7.

    Article  PubMed  CAS  Google Scholar 

  9. 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(1):7–14.

    Article  PubMed  CAS  Google Scholar 

  10. Kawasaki T, Itoh K, Uezono K, Ogaki T, Yoshimizu Y, Kobayashi S, Osaka T, Ogata M, Dhungel S, Sharma S, et al. Investigation of high salt intake in a Nepalese population with low blood pressure. J Hum Hypertens. 1993;7(2):131–40.

    PubMed  CAS  Google Scholar 

  11. Hashimoto T, Yagami F, Owada M, Sugawara T, Kawamura M. Salt preference according to a questionnaire vs. dietary salt intake estimated by a spot urine method in participants at a health check-up center. Intern Med. 2008;47(5):399–403.

    Article  PubMed  Google Scholar 

  12. Iseki K, Iseki C, Itoh K, Uezono K, Sanefuji M, Ikemiya Y, Fukiyama K, Kawasaki T. Urinary excretion of sodium and potassium in a screened cohort in Okinawa, Japan. Hypertens Res. 2002;25(5):731–6.

    Article  PubMed  Google Scholar 

  13. Kawamura M, Kusano Y, Takahashi T, Owada M, Sugawara T. Effectiveness of a spot urine method in evaluating daily salt intake in hypertensive patients taking oral antihypertensive drugs. Hypertens Res. 2006;29(6):397–402.

    Article  PubMed  CAS  Google Scholar 

  14. Tanaka T, Okamura T, Miura K, Kadowaki T, Ueshima H, Nakagawa H, Hashimoto T. A simple method to estimate populational 24-h urinary sodium and potassium excretion using a casual urine specimen. J Hum Hypertens. 2002;16(2):97–103.

    Article  PubMed  CAS  Google Scholar 

  15. Tamaki J, Kikuchi Y, Yoshita K, Takebayashi T, Chiba N, Tanaka T, Okamura T, Kasagi F, Minai J, Ueshima H. Stages of change for salt intake and urinary salt excretion: baseline results from the High-Risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) study. Hypertens Res. 2004;27(3):157–66.

    Article  PubMed  Google Scholar 

  16. Fukuda M, Motokawa M, Miyagi S, Sengo K, Muramatsu W, Kato N, Usami T, Yoshida A, Kimura G. Polynocturia in chronic kidney disease is related to natriuresis rather than to water diuresis. Nephrol Dial Transplant. 2006;21:2172–7.

    Article  PubMed  Google Scholar 

  17. Uzu T, Kimura G. Diuretics shift circadian rhythm of blood pressure from nondipper to dipper in essential hypertension. Circulation. 1999;100(15):1635–8.

    Article  PubMed  CAS  Google Scholar 

  18. Fukuda M, Yamanaka T, Mizuno M, Motokawa M, Shirasawa Y, Miyagi S, Nishio T, Yoshida A, Kimura G. Angiotensin II type 1 receptor blocker, olmesartan, restores nocturnal blood pressure decline by enhancing daytime natriuresis. J Hypertens. 2008;26(3):583–8.

    Article  PubMed  CAS  Google Scholar 

  19. Kawamura M, Hashimoto T, Owada M, Sugawara T. The influence of posture on the estimation of daily salt intake by the second morning urine method. Hypertens Res. 2010;33:505–10.

    Article  PubMed  Google Scholar 

  20. Ogihara T, Kikuchi K, Matsuoka H, Fujita T, Higaki J, Horiuchi M, Imai Y, Imaizumi T, Ito S, Iwao H, Kario K, Kawano Y, Kim-Mitsuyama S, Kimura G, Matsubara H, Matsuura H, Naruse M, Saito I, Shimada K, Shimamoto K, Suzuki H, Takishita S, Tanahashi N, Tsuchihashi T, Uchiyama M, Ueda S, Ueshima H, Umemura S, Ishimitsu T, Rakugi H. The Japanese Society of Hypertension guidelines for the management of hypertension (JSH 2009). Hypertens Res. 2009;32(1):3–107.

    Article  PubMed  CAS  Google Scholar 

  21. Japanese Society of Nephrology. Evidence-based practice guideline for the treatment of CKD. Clin Exp Nephrol. 2009;13(6):537–66.

    Google Scholar 

Download references

Acknowledgments

This study was supported by a grant from the Ministry of Health, Labor and Welfare.

Author information

Authors and Affiliations

  1. Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya, 466-8550, Japan

    Enyu Imai, Shoichi Maruyama & Seiichi Matsuo

  2. Department of CKD Initiatives, Nagoya University Graduate School of Medicine, Nagoya, Japan

    Yoshinari Yasuda, Kanako Shibata, Sawako Kato, Yu Mizutani, Junko Imai, Mutsuharu Hayashi & Hideki Kamiya

  3. Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Japan

    Masaru Horio

  4. Departmant of Cardiovascular Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan

    Toyoaki Murohara

  5. Department of Endocrinology and Diabetology, Nagoya University Graduate School of Medicine, Nagoya, Japan

    Yutaka Oiso

Authors
  1. Enyu Imai
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Yoshinari Yasuda
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Masaru Horio
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Kanako Shibata
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Sawako Kato
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Yu Mizutani
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Junko Imai
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Mutsuharu Hayashi
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Hideki Kamiya
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Yutaka Oiso
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Toyoaki Murohara
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Shoichi Maruyama
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Seiichi Matsuo
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Enyu Imai.

Additional information

A part of this study was presented at ERA-EDTA 2011 at Plague.

An erratum to this article can be found online at http://dx.doi.org/10.1007/s10157-013-0791-y.

About this article

Cite this article

Imai, E., Yasuda, Y., Horio, M. et al. Validation of the equations for estimating daily sodium excretion from spot urine in patients with chronic kidney disease. Clin Exp Nephrol 15, 861–867 (2011). https://doi.org/10.1007/s10157-011-0523-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10157-011-0523-0

Keywords

Search

Navigation