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Table 4 Predictors of completing Advance Directives and Costs (based on binary and linear model regressions of multiply imputed data)

From: Costs and advance directives at the end of life: a case of the ‘Coaching Older Adults and Carers to have their preferences Heard (COACH)’ trial

   Dependent variables for 2nd step of the regression analyses are different types of costs: figures are coefficient (Std. Err.)
  Independent variable Drugs Hospitalisation Tests, treatments & Investigations Consultations Othera Total Total (adjusted for censoring)b
n = 228 n = 228 n = 228 n = 228 n = 228 n = 228 n = 228
Predictors of Costs         
  Was an ADc completed? (1 = yes; 0 = No) 0.02 (0.24) 0.93 (0.58) 0.47 (0.32) 0.22 (0.23) 0.96 (0.51) 0.64 (0.42) 0.19 (0.11)
  Gender(1 = Female, 0 = Male) 0.05 (0.13) −0.20 (0.33) −0.22 (0.17) −0.06 (0.12) −0.29 (0.29) −0.17 (0.24) −0.05 (0.06)
  Age (in years) −0.02 (0.01)* −0.09 (0.03)* −0.06 (0.01)* −0.02 (0.01)* 0.10 (0.03)* −0.06 (0.02)* −0.01 (0.00)*
  Baseline EQ-5D 3 L score −0.15 (0.29) 0.44 (0.68) 0.44 (0.40) 0.00 (0.29) 0.27 (0.55) 0.30 (0.51) −0.05 (0.13)
  Baseline Barthel Index 0.00 (0.00) −0.01 (0.01) −0.01 (0.01) 0.00 (0.00) 0.01 (0.01) −0.01 (0.01) 0.00 (0.00)
  Baseline SMMSEd score 0.02 (0.01) 0.00 (0.03) 0.04 (0.02) * 0.03 (0.01) * 0.03 (0.03) 0.01 (0.02) 0.01 (0.01)
  Baseline GDS-15e score 0.00 (0.02) −0.08 (0.06) 0.01 (0.03) 0.01 (0.02) −0.03 (0.05) −0.06 (0.04) −0.01 (0.01)
  Body mass index 0.04 (0.01)* −0.06 (0.03) −0.01 (0.02) 0.01 (0.01) 0.03 (0.03) −0.03 (0.02) 0.00 (0.01)
  Did individual have a QoLf gain at 12 months? (1 = ‘Yes’, 0 otherwise) −0.11 (0.15) −0.20 (0.37) 0.44 (0.21) * −0.03 (0.15) 0.48 (0.28) −0.21 (0.27) −0.23 (0.17)
  Dead at 12 months (1 = Yes, 0 = No) −0.19 (0.16) 0.20 (0.39) −0.05 (0.22) −0.16 (0.15) 0.74 (0.32) * 0.09 (0.29) 0.29 (0.08) *
  Constant 8.98 (1.15)* 20.10 (3.15)* 13.1 (1.48)* 8.78 (1.01)* −4.99 (2.73) 17.13 (2.04) * 11.89 (0.47)*
  R-Squared 0.19 0.09 0.18 0.09 0.08 0.10 0.25
   The dependent variable for each type of cost in the 1st step of the regression analyses is whether or not an individual completed an Advance Directive: figures are coefficient (Std. Err.)
   Drugs Hospitalisation Tests, treatments & Investigations Consultations Othera Total Total (adjusted for censoring)b
n = 228 n = 228 n = 228 n = 228 n = 228 n = 228 n = 228
Predictors of AD completion         
  Gender (1 = Female, 0 = Male) 0.12 (0.04)* 0.10 (0.03)* 0.12 (0.04)* 0.17 (0.05)* 0.12 (0.03)* 0.10 (0.03)* 0.12 (0.03)*
  Age (in years) 0.03 (0.01)* 0.03 (0.01)* 0.03 (0.01)* 0.04 (0.01)* 0.03 (0.01)* 0.03 (0.01)* 0.04 (0.01*)
  Baseline SMMSEd score −0.02 (0.02) −0.03 (0.02) −0.03 (0.02) −0.02 (0.02) −0.02 (0.02) −0.03 (0.02) −0.03 (0.02)
  Baseline GDS-15e score 0.08 (0.03)* 0.09 (0.03)* 0.09 (0.03)* 0.09 (0.03)* 0.12 (0.03)* 0.09 (0.03)* 0.09 (0.03)*
  constant −2.92 (1.14) −2.88 (1.16) −2.66 (1.18) −3.02 (1.19) −2.94 (1.23) −2.97 (1.15) −2.98 (1.15)
  Likelihood-ratio test of independent equations χ2 = 18.60 χ2 = 34.24 χ2 = 46.01 χ2 = 26.12 χ2 = 9.93 χ2 = 37.21 χ2 = 38.60
(p < 0.01) (p < 0.01) (p < 0.01) (p < 0.01) (p < 0.01) (p < 0.01) (p < 0.01)
  1. aOther = primary care and general practice; bTotal costs calculated after adjusting for censoring using Lin’s method [64]; cAD = Advance directive; dSMMSE = Standardised Mini Mental State Examination; eGDS-15 = Geriatric Depression Scale; fQoL = Quality of life; *Statistically significant at 0.05 level