ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

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.