Study on the Correlation between Urinary Sodium and Potassium Excretion and Blood Pressure in Adult Hypertensive Inpatients of Different Sexes

Abstract

Objective. This study aims to understand the difference in the influence of urinary sodium and potassium excretion on blood pressure in patients of different sexes with hypertension by analyzing the relationship between urinary sodium and potassium excretion and blood pressure. Methods. In this cross-sectional study, 606 hospitalized patients with essential hypertension were recruited from 16 hospitals in the Shanxi Province between June 2018 and December 2019. These patients were grouped by sex, with 368 males and 238 females. Basic information and relevant serum biochemical indexes of patients in the two groups were recorded. The 24-hour urinary sodium and potassium excretion were measured, and 24-hour ambulatory blood pressure monitoring was performed simultaneously. This was done to analyze and compare the relationship between urinary sodium and urinary potassium excretion and blood pressure in adult hospitalized patients of different sexes with hypertension. Results. The 24-hour urinary sodium excretion in male patients with hypertension was significantly higher than that in female patients ( $P<0.001$ ). There was no significant difference in 24-hour urinary potassium excretion between male patients with hypertension and female patients. Spearman correlation analysis showed that 24-hour urinary sodium excretion was positively correlated with 24-hour SBP and nSBP in male patients ( $P<0.05$ ), while 24-hour urinary potassium excretion was negatively correlated with 24-hour SBP and nSBP in male patients ( $P<0.05$ ). The 24-hour urinary sodium in female patients was significantly positively correlated with 24-hour SBP, 24-hour DBP, SBP, dDBP, nSBP, and nDBP ( $P<0.01$ ). The 24-hour urinary potassium was significantly negatively correlated with nSBP ( $P<0.05$ ). Multiple stepwise linear regression showed that 24-hour urinary sodium excretion was still significantly positively correlated with 24-hour SBP and nSBP in male patients with hypertension after adjusting for various confounding factors. Conclusion. High urinary sodium and low urinary potassium excretion are closely related to elevated blood pressure in adult patients with hypertension, and there are sex differences.