Abstract P183: The Multiple Measurements of Urinary Sodium-to-Potassium Ratio Strongly Related With Home Hypertension: the Tohoku Medical Megabank Project Cohort Study

Abstract

Introduction: Recently, the balance between sodium and potassium intake, i.e. sodium-to-potassium (Na/K) ratio, has received a lot of attention for prevention of hypertension. Previous studies reported that the positive association between 24-hour urinary Na/K (uNa/K) ratio and hypertension. However, no studies have evaluated the relationship between uNa/K ratio measured by casual urine measurement and home hypertension in large populations. We aimed to clarify whether casual uNa/K ratio using the self-monitoring device was associated with home hypertension in general population. In addition, we assessed whether multiple days measurement of uNa/K ratio by casual urine increase the accuracy of the prediction of home hypertension compared with casual urine collected in a single day. Hypothesis: We assessed the hypothesis that multiple measurement of uNa/K ratio was positively associated with home hypertension, and increase the prediction of home hypertension compared with a single measurement. Methods: The subjects were over 20 years old who participated in The Tohoku Medical Megabank Project Cohort Study. Of these participants, we targeted 2,551 subjects who borrowed home blood pressure monitors (HEM-7080IC) and uNa/K ratio monitors (HEU-001F) for continuous 10 days. To assess the relationship between casual uNa/K ratio and home hypertension, we performed multiple logistic regression analyses and calculated aOR with 95% CI. We included covariate factors as age, sex, BMI and drinking status. In addition, to compare the prediction of home hypertension in multiple measurement with that in a single measurement, we calculated area under the ROC curve (AUROC) of uNa/K ratio. Home hypertension was defined as a SBP ≥ 135 mmHg and/or a DBP ≥ 85 mmHg. Results: Among 849 subjects had home hypertension (33.3%). Although uNa/K ratio was even positively associated with home hypertension by a single day (P for trend <0.01, aOR of home hypertension increase per quartile =1.11), the relationship between uNa/K ratio of multiple measurement and home hypertension was more robust (aOR of more than 5 days: 1.23 to 1.25). Similarly, AUROC of uNa/K ratio measurement for home hypertension in 5 days was larger than that in a single day. Conclusions: In conclusion, even single measurement of uNa/K ratio was positively associated with hypertension, the multiple measurement of uNa/K ratio strongly related with home hypertension. We suggested that multiple measurement of uNa/K ratio is desirable for assessing home hypertension because long term measurement of uNa/K ratio might reflect participants’ dietary balance of Na/K ratio.