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Abstract: PO2071

Estimation of Sodium Consumption by Novel Formulas Derived from 12-Hour Urine Collection

Session Information

Category: Hypertension and CVD

  • 1401 Hypertension and CVD: Epidemiology, Risk Factors, and Prevention

Authors

  • Sonuch, Pitchaporn, Mahidol University Faculty of Medicine Ramathibodi Hospital, Bangkok, Thailand
  • Kantachuvesiri, Surasak, Mahidol University Faculty of Medicine Ramathibodi Hospital, Bangkok, Thailand
Background

24-hour urine sodium excretion is the gold standard for estimating sodium intake. Several equations have been used to estimate 24-hour urine sodium excretion from spot urine samples. However, a validated formula for predicting 24-hour urine sodium excretion from 12-hour urine collection has not been established. This study aims to establish novel equations for predicting 24-hour urine sodium excretion from 12-hour urine collection and to also validate spot urine equations for predicting 24-hour urine sodium excretion.

Methods

209 adults were recruited from hospital personnel. Participants were asked to perform a 12-hour daytime, nighttime, and a random spot urine collection in 1 day. Pearson correlation was used to compare measured 24-hour sodium excretion to the estimated values from three different methods. A multivariate linear regression analysis was performed to create novel equations. Bland-Altman method was used to estimate bias and agreement between the equations.

Results

The mean 24-hour urine sodium excretion was 4,055±1,712 mg/day (male 4,307±1,694 and female 3,882±1,710 mg/day, P=0.078). The 24-hour urine sodium excretion in non-healthcare workers was higher than in healthcare workers (4,442±1,865 and 3,617±1,406 mg/day respectively, P<0.001). Estimated urine sodium excretion from 3 different equations using spot urine samples showed moderate correlation with actual 24-hour urine sodium excretion (r=0.54, P<0.001 for Kawasaki; r=0.57, P<0.001 for Tanaka; r=0.60, P<0.001 for INTERSALT). Novel equations for predicting 24-hour urine sodium excretion was then developed using variables derived from 12-hour daytime urine collection, 12-hour nighttime urine collection, and random spot urine samples which showed strong correlation with actual measured values; r=0.88, P<0.001, r=0.83, P<0.001, r=0.67, P<0.001 respectively. Bland-Altman plots indicated good agreement between predicted values and actual 24-hour urine sodium excretion using the new equations, with biases for 12-hour daytime urine collection of -0.28 mmol/day (95%CI: -5.09 to 4.53), for 12-hour nighttime urine collection of 0.85 mmol/day (95%CI: -4.86 to 6.56), and for random spot urine sample of 0.90 mmol/day (95%CI: -6.66 to 8.45).

Conclusion

Newly derived equations from 12-hour daytime urine collection and 12-hour nighttime urine collection can accurately predict 24-hour urine sodium excretion.

Funding

  • Government Support - Non-U.S.