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Lack of correlation between two methods for the assessment of salt sensitivity in essential hypertension

Abstract

The existence of a heterogeneous blood pressure (BP) response to salt intake, a phenomenon known as salt sensitivity, has increasingly become a subject of clinical hypertension research, and has important clinical and prognostic implications. However, two different methodologies are currently used to diagnose salt sensitivity. The aim of the present study was to compare the BP response to intravenous sodium load and depletion on the one hand, and to changes in dietary salt intake on the other, in order to assess salt sensitivity in a group of essential hypertensive patients. Twenty-nine essential hypertensives underwent two different procedures separated by 1 month: a dietary test consisting of a 2-week period of low (20 mmol/day) and high (260 mmol/day) salt intakes, and an intravenous test consisting of a 2 litre saline load over a 4-h period, followed by 1 day of low (20 mmol) salt intake and furosemide (40 mg/8 h orally) administration. BP was registered at the end of every period using 24-h ambulatory BP monitoring. In the whole group of hypertensive patients studied, both low salt intake and furosemide administration significantly (P < 0.01) decreased mean BP. Correlation coefficients of BP changes obtained using the two methodologies were between 0.3 and 0.4. Moreover, coefficients of agreement between the oral and the intravenous tests, using several cut points for BP changes, were systematically below 0.5, thus indicating a misclassification of salt sensitivity greater than 50%, depending on the method used. None of the cut points for BP changes during furosemide administration showed a good combination of sensitivity and specificity compared with changes in response to low dietary salt. The present results indicate that the diagnosis of salt-sensitive hypertension should be based on the BP response to changes in dietary salt intake, while BP response to saline and furosemide administration leads to a systematic misclassification of more than 50% of patients, even using different cutpoints for changes in BP.

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References

  1. Muntzel M, Drüeke T . A comprehensive review of the salt and blood pressure relationship Am J Hypertens 1992 5: 1S–42S

    Article  CAS  Google Scholar 

  2. Campese VM . Salt sensitivity in hypertension. Renal and cardiovascular implications Hypertension 1994 23: 531–550

    Article  CAS  Google Scholar 

  3. Weinberger MH . Salt sensitivity of blood pressure in humans Hypertension 1996 27: 481–490

    Article  CAS  Google Scholar 

  4. de la Sierra A et al. Assessment of salt sensitivity in essential hypertension by 24-h ambulatory blood pressure monitoring Am J Hypertens 1995 8: 970–977

    Article  CAS  Google Scholar 

  5. Giner V et al. Renin-angiotensin system genetic polymorphisms and salt sensitivity in essential hypertension Hypertension 2000 35: 512–517

    Article  CAS  Google Scholar 

  6. de la Sierra A et al. Fluid, ionic and hormonal changes induced by high salt intake in salt-sensitive and salt-resistant hypertensive patients Clin Sci 1996 91: 155–161

    Article  CAS  Google Scholar 

  7. Bragulat E, de la Sierra A, Antonio MT, Coca A . Endothelial dysfunction in salt sensitive hypertension Hypertension 2001 37: 444–448

    Article  CAS  Google Scholar 

  8. de la Sierra A et al. Increased left ventricular mass in salt-sensitive hypertensive patients J Hum Hypertens 1996 10: 795–799

    CAS  PubMed  Google Scholar 

  9. Morimoto A et al. Sodium sensitivity and cardiovascular events in patients with essential hypertension Lancet 1997 350: 1734–1737

    Article  CAS  Google Scholar 

  10. Sullivan JM . Salt sensitivity. Definition, conception, methodology, and long-term issues Hypertension 1991 17 (Suppl I): 161–168

    Google Scholar 

  11. Weinberger MH, Stegner JE, Fineberg NS . A comparison of two tests for the assessment of blood pressure responses to sodium Am J Hypertens 1993 6: 179–184

    Article  CAS  Google Scholar 

  12. Sharma AM, Schorr U, Cetto C, Distler A . Dietary v intravenous salt loading for the assessment of salt sensitivity in normotensive man Am J Hypertens 1994 7: 1070–1075

    Article  CAS  Google Scholar 

  13. Galletti F et al. Evaluation of a rapid protocol for the assessment of salt sensitivity against the blood pressure response to dietary sodium chloride restriction Am J Hypertens 1997 10: 462–466

    Article  CAS  Google Scholar 

  14. Cusi D et al. Polymorphisms of alpha-adducin and salt sensitivity in patients with essential hypertension Lancet 1997 349: 1353–1357

    Article  CAS  Google Scholar 

  15. Poch E et al. Genetic variation of the γ subunit of the epithelial Na+ channel and essential hypertension. Relationship with salt sensitivity Am J Hypertens 2000 13: 648–653

    Article  CAS  Google Scholar 

  16. Gradual NA, Galløe AM, Garred P . Effect of sodium restriction on blood pressure, renin, aldosterone, catecholamines, cholesterols, and triglyceride. A meta-analysis JAMA 1998 279: 1383–1391

    Article  Google Scholar 

  17. Chobanian AV, Hill M . National Heart, Lung, and Blood Institute Workshop on sodium and blood pressure. A critical review of current scientific evidence Hypertension 2000 35: 858–863

    Article  CAS  Google Scholar 

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de la Sierra, A., Giner, V., Bragulat, E. et al. Lack of correlation between two methods for the assessment of salt sensitivity in essential hypertension. J Hum Hypertens 16, 255–260 (2002). https://doi.org/10.1038/sj.jhh.1001375

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