| Background: High salt consumption is closely associated to the ventricular hypertrophy,renal damage,and other target organ damages in patients with hypertension.Therefore,sodium intake should be accurately assessed to carry out targeted treatment in hypertensive patients,which is one of the important strategies in blood pressure management.The 24‐hour urinary sodium(UNa)measure has been used as the gold standard to assess sodium intake.Since tedious process and long‐time collection of24‐hour urinary,this method is difficult to apply in large-scale studies.Other methods were developed to predict sodium intake by measure the concentration of spot urinary sodium/creatinine.These methods including Kawasaki,Tanaka,INTERSALT,Mage,Uechi,Toft,Cockcroft-Gault,Nerbass which were based on European,American or Japanese population had been developed for a long time.Based on Chinese people and changes in salt intake,the new method was developed by Professor Sun Ningling.The validity of the above methods needs further verification.Objective: The objective was to evaluate the accuracy of nine formulas using spot urinary sample for 24-h UNa prediction in patients living in northeast China.And another objective was to study the relationship between 24-h UNa and target organ damage in patients with essential hypertension.Method: In the first part of the study,there were 672 hospitalized patients enrolled from January 2019 to July 2020 at the department of hypertension in our hospital.Nine formulas were used to predict 24-h UNa excretion via spot morning urinary samples.Actual UNa excretion was measured from 24-h urine samples.The estimated value was compared with the actual value by examining biases,the intraclass correlation coefficients(ICC),and Bland–Altman plots.The participants were divided into subgroups based on actual urinary sodium excretion or sex.The performance of the nine formulas was compared across sex and salt intake subgroups.Furthermore,the relative difference and absolute differences were analyzed at the individual level.In the second part of the study,there were 505 hypertensive patients from the first part of the study.Blood pressure and heart,kidney,vascular target organ damage of subjects with different levels of salt intake were analysis.Results: In the first part of the study,the average excretion of urinary sodium was3.16±1.64 g/day.Only the estimated 24-h UNa excretion calculated by the Nerbass equation underestimated the urinary sodium excretion compared with the actual urinary sodium excretion.The least bias of the estimated urinary sodium was 0.07±1.44 g/day for the INTERSALT,whereas the largest bias was 1.67±1.64 g/day for the Kawasaki.The bias the estimated urinary sodium was 0.07±1.44 g/day for the new method.The ICC was 0.608 for Kawasaki,0.598 for Toft,0.563 for INTERSALT,0.558 for Cockcroft-Gault,0.551 for Nerbass,0.534 for new method,0.533 for Mage,0.507 for Uechi,0.480 for Tanaka.The mean actual UNa excretion of the male participants was3.60±1.81 g/day,which was higher than that of the female participants(2.63±1.20g/day).The least bias for the estimated UNa of the male subgroup was 0.06±1.65 g/day for the new method,whereas the highest bias was 1.50±1.84 g/day for the Kawasaki.The least bias for the estimated UNa of the female subgroup was-0.08±1.10 g/day for the INTERSALT method,whereas the highest bias was 1.92±1.33 g/day for the Kawasaki.The least mean biases in the lower salt intake subgroup and the moderate salt intake subgroup were 0.80 and 0.03 g/day,respectively,and were calculated by the Nerbass and INTERSALT methods.The least mean bias in the higher salt intake subgroup was-0.41 g/day for the Kawasaki method.In the second part of the study,blood pressure,left ventricular mass,left ventricular mass index,24-h urine protein excretion,urinary albumin/creatinine ratio and ankle brachial index was significantly higher in the higher salt intake subgroup,and there was significant difference between the three subgroups which was based on actual urinary sodium excretion.However,there was no difference between the three subgroups in the E/A,E/e’,EDT,e GFR,Cystatin C,pulse wave velocity,flow mediated dilation,carotid intimal thickness.Conclusions: A morning voiding urine sample may be a valid low-burden,low-cost alternative for the estimation of mean salt intake.Specifically,the INTERSALT and new method may exhibit a good performance in terms of mean 24-h sodium estimation for the hospitalized patients living in Northeast China.Patients who had high sodium consumption or preference for a salty diet are more prone to develop higher blood pressure and severe hypertensive target organ damage. |
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