The Relationship Between Sodium Intake and Urinary Potassium Sodium Ratio with Blood Pressure in Elderly Hypertensive Patients

Electrolyte imbalance is a crucial determinant in the pathophysiology of hypertension in the elderly, but the accuracy of intake assessment through dietary survey methods is often biased due to cognitive decline. This study aims to compare the strength of association between estimated sodium intake derived from dietary recall and the 24-hour urinary potassium-to-sodium (K/Na) ratio with blood pressure. This analytical observational study with a cross-sectional design involved 98 hypertensive patients aged ≥60 years who were recruited through consecutive sampling in the working area of the Sukamerindu Community Health Center, Bengkulu City. Dietary intake was assessed using a 2×24-hour recall, and urinary electrolyte excretion was measured using the ion-selective electrode method. The analysis showed that the correlation between recall-based sodium intake and blood pressure was weak and inconsistent. In contrast, the urinary K/Na ratio showed a strong and significant negative correlation with systolic and diastolic blood pressure. Steiger's Z test confirmed that urinary biomarkers had statistically superior predictive validity compared to subjective dietary data (p < 0.05). These findings confirm that the urinary K/Na ratio is a more precise biological indicator of hemodynamics in the elderly than dietary estimates, and underscore the importance of nutritional interventions that increase potassium intake to achieve optimal electrolyte ratios.