TABLE I.
Test–Retest Reproducibility and Construct Validity of the Type and Volume of Fluid Intake as Measured by the Questionnaire Based Voiding Diary (QVD)
| Type of fluid intake | Median (IQR) daily intake by QVD (visit 1) | Median (IQR) daily intake by QVD (visit 2) | Test–retest reliability (ICC)a | Median (IQR) daily intake by bladder diary | Correlation with the bladder diary (r)b |
|---|---|---|---|---|---|
| Total fluid (ml) | 2,371 (820–2,867) | 2,406 (823–2,901) | 0.77 | 2,265 (836–2,796) | 0.75 |
| Caffeinated tea or coffee (ml) | 710 (237–1,248) | 730 (240–1,303) | 0.86 | 746 (255–1,368) | 0.83 |
| Decaffeinated tea or coffee (ml) | 360 (240–720) | 341 (240–689) | 0.81 | 354 (200–750) | 0.79 |
| Carbonated drinks (ml) | 390 (240–1,080) | 366 (240–1,145) | 0.87 | 343 (229–1,285) | 0.81 |
| Water (ml) | 1,275 (720–1,920) | 1,301 (685–1,746) | 0.76 | 1,184 (450–1,699) | 0.71 |
| Other fluids (milk, fruit juice, alcohol) (ml) | 347 (200–459) | 401 (157–549) | 0.71 | 466 (134–623) | 0.65 |
IQR, interquartile range.
a
ICC, intraclass correlation coefficient, P < 0.01 for each.
b
Spearman correlation coefficient, P < 0.01 for each.