Abstract: SA-PO1111

Urinary Sodium-to-Potassium Ratio Associated with Normal Blood Pressure

Session Information

  • Salt and Hypertension
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Hypertension

  • 1104 Hypertension: Clinical and Translational - Salt and Hypertension

Authors

  • Banerjee, Tanushree, University of California, San Francisco, San Francisco, California, United States
  • Sebastian, Anthony, None, San Francisco, California, United States
  • Frassetto, Lynda A., University of California San Francisco, San Francisco, California, United States
Background

Higher levels of sodium intake are reported to be associated with higher blood pressure (BP). Whether this relationship is stronger with urinary sodium to potassium ratio (U[Na/K]) and in those with diagnosed and pre hypertension is not well determined.

Methods

We studied 188 older healthy patients randomized to potassium bicarbonate 30, 60, or 90 mmol/d (KBC treatment) or placebo, for up to 36 months. The 24-hour urine and arterialized blood collections were done at baseline and then at the subsequent follow-up visits. The simple Pearson correlation coefficients (r) between urinary sodium, potassium and U[Na/K], urine pH and systolic and diastolic BP levels were calculated at baseline. The correlation coefficients were also calculated for the dietary equations estimating acid load described as net endogenous acid production (NEAP) by Frassetto, and potential renal acid load (PRAL) by Remer and Manz with urine pH. The association of U[Na/K] and arterial BP was investigated using mixed-effects model, with adjustment for age, weight, height, creatinine clearance, and treatment.

Results

Correlation analyses results are shown in Table 1. Mean arterial BP increased significantly with an increase in the urinary Na/K ratio (β [95% CI]: 0.28 [0.17-0.44]). There was effect modification by treatment (p interaction=0.02). Stratified models by treatment showed a significant association between U[Na/K] and mean arterial BP in those receiving KBC (0.32 [0.20-0.47]) while no significant association was observed in case of placebo (0.24 [-0.02-0.51]). In case of diagnosed and pre hypertension, we did not find a significant association between U[Na/K] and arterial BP (0.05 [-0.22-0.18] in diagnosed and 0.02 [-0.31-0.24] in undiagnosed hypertension). However, in normotensives a significant association was noted (0.31 [0.18-0.49]).

Conclusion

The ratio of urinary Na/K was independently associated with arterial BP even after adjustment for potential confounders, and this association may be more pronounced in normotensives.

 Systolic BPDiastolic BPUrine pH
Urine Na0.04-0.07-0.07
Urine K-0.03-0.050.09
Urine Na/K ratio-0.06-0.08-0.19 (p=0.007)
NEAP  -0.25 (p=0.008)
PRAL with sodium chloride  -0.37 (p<0.0001)
PRAL without sodium chloride  -0.36 (p<0.0001)

Funding

  • Private Foundation Support