Skip to main content

Table 1 Parameterization of the group variable in the multiple linear regression models

From: Fluid balance, change in serum creatinine and urine output as markers of acute kidney injury post cardiac surgery: an observational study

  Parameterization (corresponding parameter in the model)
Group X1 (β1) X2 (β2) X3 (β3) X4 (β4)
1) SCr-, UO-, FOL- 0 0 0 0
2) SCr-, UO-, FOL+ 1 0 0 0
3) SCr-, UO+, FOL- 1 1 0 0
4) SCr-, UO+, FOL+ 1 1 1 0
5) SCr+ 1 1 1 1
  1. Each group variable or combination of SCr/UO/FOL status was parameterized as above so that the group variable could be considered as an ordinal variable in the multiple linear regression model. β1 indicates a comparison between SCr-, UO-, FOL- and SCr-, UO-, FOL+, β2 indicates a comparison between SCr-, UO-, FOL + and SCr-, UO+, FOL- and so forth.
  2. SCr+: Meeting the criteria of Change in SCr ≥ 26.5 µmol/L; SCr -: Not meeting the Change in SCr criteria.
  3. UO+: Meeting the criteria of Urine Output ≤0.5 cc/kg/hour for greater than 6 hours; UO-: Not meeting the Urine Output criteria.
  4. FOL+: Meeting the criteria of Fluid Overload, defined as fluid balance ≥ 6.5 cc/kg; FOL-: Not meeting the Fluid Overload criteria.