Association between blood pressure control in hypertension and urine sodium to potassium ratio: From the Korea National Health and Nutrition Examination Survey (2016–2021)

by Youngmin Yoon, Minkook Son

Hypertension (HTN) is linked to an enhanced risk of chronic kidney disease and cardiovascular disease. While sodium and potassium intake affect blood pressure (BP) control, the urine sodium-to-potassium (Na/K) ratio, which reflects dietary balance and renal regulation of these electrolytes, could be associated with BP. This study aimed to evaluate the independent association between urine Na/K and uncontrolled HTN.

Data were collected from the Korea National Health and Nutrition Examination Survey from 2016 to 2021. A total of 5,770 participants diagnosed with HTN were enrolled in this study. Uncontrolled HTN was characterized by a systolic blood pressure (SBP) ≥ 140 mmHg or diastolic blood pressure (DBP) ≥ 90 mmHg. Logistic regression analysis was used to assess the relationship between urine Na/K and the risk of uncontrolled HTN.

The urine Na/K was positively correlated with both SBP and mean arterial pressure. Higher urine Na/K was significantly associated with an increased risk of uncontrolled HTN using both continuous (odds ratio [95% confidence interval] 1.13 [1.09–1.16], P <0.01]) and across quartile values (with Q1 as a reference; Q2: 1.26 [1.06–1.49], P = 0.01; Q3: 1.50 [1.27–1.78], P <0.01; Q4: 1.85 [1.55–2.17], P < 0.01). The subgroup analysis also showed that higher urine Na/K were significantly related to the risk of uncontrolled HTN in the presence of proteinuria or CKD.

Urine Na/K ratio is independently associated with uncontrolled HTN in the general population and in patients with CKD. Our findings suggest that monitoring the urine Na/K could serve as an effective tool for identifying subjects at risk of uncontrolled HTN.