Table 2:

Impact of the after-hours premium value on emergency department visits between 2002/03 and 2005/06 based on fixed-effects regression models with and without monthly effects

VariableAll ED visitsVery urgent ED visitsUrgent ED visitsLess-urgent ED visits
No monthly effects β (95% CI)*With monthly effects β (95% CI)*No monthly effects β (95% CI)*With monthly effects β (95% CI)*No monthly effects β (95% CI)*With monthly effects β (95% CI)*No monthly effects β (95% CI)*With monthly effects β (95% CI)*
After-hours premium
 10%−0.09 (−0.41 to 0.23)0.23 (−0.10 to 0.55)0.73 (0.63 to 0.82)0.65 (0.55 to 0.75)0.87 (0.70 to 1.05)0.84 (0.66 to 1.02)−1.69 (−1.91 to −1.48)−1.26 (1.48 to −1.04)
 15%1.31 (0.98 to 1.64)1.50 (1.17 to 1.83)1.15 (1.05 to 1.24)1.09 (0.99 to 1.19)1.74 (1.55 to 1.93)1.71 (1.52 to 1.90)−1.58 (−1.80 to −1.35)−1.29 (−1.52 to −1.07)
 Change from 10% to 15%1.40 (1.07 to 1.73)1.28 (0.95 to 1.60)0.42 (0.32 to 0.52)0.44 (0.34 to 0.54)0.87 (0.68 to 1.06)0.87 (0.68 to 1.06)0.11 (−0.10 to 0.32)−0.04 (−0.24 to 0.18)
Month
 February−1.26 (−1.58 to −0.93)−0.18 (−0.28 to −0.07)−0.38 (−0.58 to −0.18)−0.69 (−0.91 to −0.48)
 March1.29 (0.95 to 1.62)0.28 (0.17 to 0.39)0.63 (0.42 to 0.84)0.38 (0.16 to 0.60)
 April−0.93 (−1.27 to −0.60)−0.47 (−0.57 to −0.36)−0.54 (−0.74 to −0.34)0.07 (0.15 to 0.30)
 May1.48 (1.14 to 1.82)−0.15 (−0.26 to −0.04)0.22 (0.02 to 0.43)1.40 (1.17 to 1.64)
 June1.12 (0.78 to 1.46)−0.24 (−0.35 to −0.14)−0.17 (−0.38 to 0.03)1.54 (1.31 to 1.77)
 July3.18 (2.82 to 3.54)−0.16 (−0.27 to −0.05)0.46 (0.25 to 0.67)2.884 (2.639 to 3.129)
 August3.27 (2.91 to 3.63)−0.14 (−0.25 to −0.03)0.56 (0.36 to 0.77)2.84 (2.60 to 3.09)
 September1.58 (1.24 to 1.92)−0.02 (−0.13 to 0.09)0.21 (< 0.01 to 0.41)1.39 (1.16 to 1.63)
 October0.73 (0.39 to 1.08)−0.08 (−0.19 to 0.02)0.07 (−0.14 to 0.28)0.75 (0.52 to 0.98)
 November−0.44 (−0.77 to −0.10)−0.14 (−0.24 to −0.03)−0.159 (−0.362 to 0.044)−0.14 (−0.36 to 0.08)
 December1.01 (0.68 to 1.35)−0.08 (−0.18 to 0.02)0.37 (0.16 to 0.58)0.72 (0.50 to 0.94)
Patient age, 5 yr0.25 (−0.02 to 0.52)0.18 (−0.09 to 0.45)0.82 (0.75 to 0.90)0.84 (0.76 to 0.92)0.78 (0.63 to 0.94)0.80 (0.64 to 0.95)−1.36 (−1.54 to −1.17)−1.45 (−1.64 to −1.27)
Low income−0.43 (−0.80 to −0.06)−0.43 (−0.80 to −0.06)< 0.00 (−0.11 to 0.11)< 0.00 (−0.11 to 0.11)−0.23 (−0.45 to −0.02)−0.23 (−0.45 to −0.02)−0.19 (−0.43 to 0.04)−0.20 (−0.43 to 0.04)
ADG score−2.01 (−2.08 to −1.94)−2.01 (−2.08 to −1.94)−0.22 (−0.24 to −0.20)−0.22 (−0.24 to −0.20)−0.85 (−0.90 to −0.81)−0.85 (−0.90 to −0.81)−0.94 (−0.98 to −0.90)−0.94 (0.98 to −0.90)
Physician age, yr0.03 (−0.37 to 0.43)0.03 (−0.37 to 0.42)0.04 (−0.08 to 0.16)0.04 (−0.07 to 0.16)−0.01 (−0.24 to 0.21)−0.01 (−0.24 to 0.21)> 0.00 (−0.27 to 0.27)< 0.00 (−0.27 to 0.26)
Physician age, yr squared< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)< 0.00 (< 0.00 to > 0.00)
Years since graduation−0.09 (−0.28 to 0.11)−0.09 (−0.28 to 0.11)−0.07 (−0.12 to −0.01)−0.07 (−0.12 to −0.01)−0.03 (−0.13 to 0.08)−0.03 (−0.13 to 0.08)0.01 (−0.13 to 0.14)0.01 (−0.13 to 0.14)
Years since graduation, squared> 0.00 (< 0.00 to 0.01)> 0.00 (< 0.00 to 0.01)> 0.00 (< 0.00 to > 0.00)> 0.00 (< 0.00 to > 0.00)> 0.00 (< 0.00 to > 0.00)> 0.00 (< 0.00 to > 0.00)0.00 (< 0.00 to > 0.00)0.00 (< 0.00 to > 0.00)
Female physician0.60 (0.07 to 1.13)0.59 (0.06 to 1.12)0.10 (−0.04 to 0.23)0.10 (−0.04 to 0.23)0.35 (0.05 to 0.64)0.35 (0.05 to 0.64)0.16 (−0.19 to 0.51)0.15 (−0.20 to 0.50)
International medical graduate0.04 (−0.66 to 0.74)0.05 (−0.65 to 0.75)0.16 (−0.02 to 0.34)0.16 (−0.03 to 0.34)0.09 (−0.30 to 0.48)0.09 (−0.30 to 0.48)−0.21 (−0.66 to 0.24)−0.20 (−0.65 to 0.25)
Group size0.01 (> 0.00 to 0.02)> 0.00 (< 0.00 to 0.01)0.01 (> 0.00 to 0.01)0.01 (> 0.00 to 0.01)< 0.00 (−0.01 to > 0.00)< 0.00 (−0.01 to > 0.00)> 0.00 (0.00 to 0.01)> 0.00 (< 0.00 to > 0.00)
  • Note: ADG = aggregated diagnosis group, CI = confidence interval, ED = emergency department.

  • * β coefficients interpreted as the change in the number of ED visits per 1000 patients per month. For confidence intervals, standard errors were clustered at the patient and physician levels.

  • Reference group: after-hours premium value of 0%.

  • Reference group: January.