Supplemental Figure 1 Absolute difference distributions of the Kawasaki,
INTERSALT, Tanaka, SunSMU, and SunPM equation for estimating 24-h urinary sodium excretion. INTERSALT, International Cooperative Study on Salt, Other Factors, and Blood Pressure.
Supplemental Figure 2 Bland-Altman plots of the difference between measured and estimated 24-h urinary sodium excretion (24-h USE) on the same day, based on International Cooperative Study on Salt, Other Factors, and Blood Pressure
(INTERSALT) equation using overnight specimen (A), second morning urine specimen (B), post meridiem specimen (C), and evening specimen (D). The dashed line represents the mean of difference. The 2-dots-dashed lines represent the 95% limits of agreement.
The difference is equal to the estimated 24-h USE minus measured 24-h USE, and the mean value is equal to the sum of estimated and measured 24-h USE divided by 2.
Supplemental Figure 3 Bland-Altman plots of the difference between measured and estimated 24-h urinary sodium excretion (24-h USE) on the same day, based on Tanaka equation using overnight specimen (A), second morning urine specimen (B), post
meridiem specimen (C), and evening specimen (D). The dashed line represents the mean of difference. The 2-dots-dashed lines represent the 95% limits of agreement. The difference is equal to the estimated 24-h USE minus measured 24-h USE, and the mean value is equal to the sum of estimated and measured 24-h USE divided by 2.
Supplemental Table 1. Sensitivity analysis of estimated 24-h USE from published equations a Equation 24-h USE b (mean ± SD c) (mg/day) rs d
P value e Mean difference f (95% CI g) (mg/day) RMS h
Measured value 4558.25 ± 1908.75 Reference Reference Reference Reference
Kawasaki 5385.11 ± 1536.31 i 0.283 0.005 985.70 (516.38, 1455.03) 6.96
INTERSALT j 3163.80 ± 737.09 i 0.178 0.078 -1208.98 (-1672.65, -745.31) 7.39
Tanaka 4391.16 ± 1129.20 0.490 < 0.001 18.39 (-398.48, 435.25) 4.72
SunSMU 3674.85 ± 945.32 i 0.159 0.118 -724.55 (-1200.23, -248.88) 6.64
SunPM 4306.72 ± 1008.35 0.369 < 0.001 -203.92 (-658.54, 250.71) 5.44
a One participant did not void during SMU periods, three participants did not void during afternoon period, so the sample size of
Kawasaki, INTERSALT, Tanaka, SunSMU and SunPM equation were 98, 99, 99, 98 and 96, respectively; b 24-h USE, 24-hour urinary sodium excretion; c SD, standard deviation; d rs, Spearman correlation coefficient; e The significance test of correlation coefficient; f Mean difference, estimated minus measured 24-h USE; g 95% CI, 95% confidence interval; h RMS, residual mean square; i Significantly different from measured 24-h USE assessed with Wilcoxon’s Signed Rank test; j INTERSALT, International Cooperative Study on Salt, Other Factors, and Blood Pressure.
Supplemental Table 2. Sensitivity analysis of estimated 24-h USE from published equations by each timing of urine spot collections a Equation Estimated 24-h USE b (mean ± SD c) (mg/day) rs d
P value e Mean difference f (95% CI g) (mg/day) RMS h INTERSALT i
overnight 2932.92 ± 635.25 j 0.294 0.003 -1443.24 (-1903.56, -982.91) 7.92
SMU k 3086.91 ± 672.98 j 0.161 0.114 -1312.49 (-1780.90, -844.09) 7.74
PM l 3215.71 ± 705.17 j 0.215 0.036 -1180.26 (-1640.68, -719.83) 7.08
evening 3237.35 ± 666.09 j 0.282 0.006 -1253.47 (-1709.38, -797.57) 7.11
Tanaka
overnight 3515.92 ± 850.88 j 0.435 < 0.001 -860.24 (-1312.73, -407.75) 6.30
SMU 3969.16 ± 920.37 0.347 < 0.001 -430.24 (-865.95, 5.47) 5.30
PM 4711.67 ± 1030.06 j 0.519 < 0.001 315.70 (-106.72, 738.11) 4.81
evening 4503.14 ± 971.41 0.507 < 0.001 12.32 (-420.96, 445.61) 4.90
a One participants did not void during overnight and SMU period, three during afternoon period, and four during the evening period, so the sample size of overnight, SMU, afternoon and evening specimens were 98, 98, 96 and 95, respectively; b 24-h USE, 24-hour urinary sodium excretion; c SD, standard deviation; d rs, Spearman correlation coefficient; e The significance test of correlation
coefficient; f Mean difference, estimated minus measured 24-h USE; g 95% CI, 95% confidence interval; h RMS, residual mean square;
i INTERSALT, International Cooperative Study on Salt, Other Factors, and Blood Pressure; j Significantly different from measured 24- h USE assessed with Wilcoxon’s Signed Rank test; k SMU, second morning urine; l PM, post meridiem.
