| Background: Hypertension is one of the most important factors for cardiovasculardisease in China. According to the data reported, more than two hundred million peoplein our country have high blood pressure. Effective control of blood pressure inhypertensive patients has become a major public health concern worldwide[1].Epidemiological research over the past century, reported that there is a closerelationship between blood pressure and salt intake. Therefore, salt intake is animportant environmental risk factor for hypertension, which is influenced by diet,culture and behavior. Excessive salt intake has become an imperil factor of hypertensionmorbidity in our country population. One survey in northern China suggested that58.6%of patients with high blood pressure are sensitive to salt intake[2].When daily saltintake is low, not only the incidence of hypertension but also the complications arelower, however, both the incidence of hypertension and its complications increase withthe increase of salt intake accordingly. The salt intake restriction is most important inprevention and treatment of hypertension. INTERMAP (International Study onMicronutrient and Blood Pressure) showed, the target of blood pressure control can beachieved by reducing the intake of salt and sodium/potassium ratio also.[3]Someresearchers also analyzed clinical trial on salt restriction stated that if salt intake reducedto6g per day, systolic blood pressure of the people could lower by2.2mmHg. Aftersalt restriction for short term in hypertensive patients, the systolic blood pressure anddiastolic blood pressure of patients decrease around4.9mmHg and2.6mmHgrespectively. In recent years, some studies suggested that, the ambulatory bloodpressure monitoring (ABPM) is one of the important means for evaluating bloodpressure circadian rhythm and24-hour heart rate (HR). Among the salt sensitivehypertension patients, disappearing of night dippers and24hHR accelerating are directlyrelated to sodium load. Therefore, abnormal blood pressure circadian rhythm and accelerating in the heart rate are expected to be one of the evaluation indexes for saltsensitive hypertension.Objective: To observe ABPM blood pressure variation in hypertension patientsbefore and after the low salt diet and also to compare the effects of low salt diet inhypertension patients with different salt sensitivity.Methods: The65patients,18-75years old, admitted to the First Affiliated Hospital ofDalian Medical University from December2012to March2013, were enrolled in thisstudy. In this study, patients were diagnosed hypertension according to “the2010ChineseHypertension Guideline”. The65patients were divided into3groups according to the24-hour heart rate and blood pressure circadian rhythm. Medical history and biochemicalinvestigations such as fasting blood glucose (FBG), uric acid (UA); creatinine (CRE), etc.were collected as patients’ baseline characteristics. During low salt diet intervention overone week, the subjects were given hospital meal according to salt restriction guideline, inwhich the sodium intake was restricted to6g by the nutritionist of our hospital. Theeffectiveness of low salt diet was assessed by urine sodium investigation. The ambulatoryblood pressure monitoring was conducted on the end of7thday of the low salt phase. TheSpacelabs90217type ambulatory blood pressure monitoring system was used in ourstudy. According to HR and24h blood pressure circadian rhythm, patients can be dividedinto three groups as low, medium and high risk group. The SPSS17.0statistical packageand EXCEL2007are applied for statistical processing and analyzing; the continuousvariables are demonstrated in form of “mean±standard deviation”; Paired t test areapplied to compare the results before and after the intervention over salt intake, theclassification variables compared by chi-square test, two sided P <0.05is regarded asstatistical significant.Results:1.The comparison of basic data between the three different groups did notshow the statistical significance (P>0.05)[age, body mass index (BMI), smoking, TG,LDL-C, TC, HDL-C, FBG, UA, Cre].2. The comparison of urine sodium values ofeach group is decreased significantly after low sodium diet,(P <0.01,0.05,<0.01,<0.01respectively).3. The comparison of ABPM between each group before and aftersalt limitation showed that the blood pressure of participants in low and medium riskgroup tends to decrease before and after the salt restriction, but there is no statisticaldifference between each group; but the blood pressure in the high-risk group decreasedobviously after the low sodium diet, especially in24h systolic blood pressure, diastolic blood pressure, daytime diastolic blood pressure, nocturnal systolic pressure, andnighttime diastolic blood pressure, there was statistical significant in these parameters(P=0.01,0.01,0.04,<0.01,<0.01).4. The comparison of blood pressure before andafter salt restriction in each group resulted that the high-risk group of nighttime systolicblood pressure, diastolic blood pressure decreased significantly when compared to lowand moderate risk group; and it was statistically significant (P <0.01,<0.01respectively).Conclusion:1. Low salt diet shows a better effect on decreasing blood pressure inhigh risk salt sensitive hypertensive patients than low and intermediate risk.2. The lowsalt diet shows better effect in nocturnal blood pressure decreasing in high risk sodiumsensitive hypertensive patients, whereas the nocturnal blood pressure lowering effect isnot significant in low or moderate risk salt sensitive hypertensive patients.3. Saltsensitive hypertensive patients could be assessed by the combination of ABPM and HR,and low salt diet should be strongly suggested in those people. So that, we caneffectively control blood pressure in high risk salt sensitive hypertension and leading tothe prevention of target organ damage in clinical practice eventually. |
PDF Full Text Request