Feasibility and accuracy of Tanaka and SH2 methods used to estimate the 24-hour urinary sodium excretion of hypertension patients in Shanghai / 解放军医学杂志

ABSTRACT

Objective To validate and evaluate the feasibility and accuracy of Tanaka (T method) and SH2 (S method) used to estimate the 24-hour urinary sodium excretion of patients in Shanghai with hypertension. Methods A hundred and eighty hypertensive patients, hospitalized in the Internal Medicine Ward of Changhai Hospital affiliated to Navy Medical University from January 2017 to January 2018, were enrolled in present study. The specimens were collected of morning urine, afternoon urine, evening urine and the completed 24h urine, and the levels of sodium, potassium and creatinine in urine specimens were detected. The differences of estimation value calculated by T method and S method were compared, and the consistency of estimated value and actual urinary sodium excretion were compared by Bland-Altman plots respectively. Results There were 122 patients were enrolled in the final statistical analysis. The average urinary sodium excretion was 151.02mmol (about 8.83g salt). The average deviation values estimated by T method at 3 time points were 34.99, 22.72 and 48.76mmol, and estimated by S method were –6.83, –6.82, –6.31mmol. The intra-group correlation coefficient (ICC) was higher of T method in morning urine specimen and of S method in three time spots urine specimens. Bland-Altman plots showed that the higher the level of 24h urine sodium excretion, the greater the bias of S method with a linear trend. Conclusion Because of the varying degrees of limitation, both T and S methods are not suitable for estimating the individual 24h urinary sodium excretion. The two methods are suitable for estimating the average 24h urinary sodium level of population, while S method is more accurate than T method.