Change in after-hours premium | All ED visits | Very urgent ED visits | ||||
---|---|---|---|---|---|---|
IPW β (95% CI)† | CBPS β (95% CI)† | Entropy balancing β (95% CI)† | IPW β (95% CI)† | CBPS β (95% CI)† | Entropy balancing β (95% CI)† | |
Any timing | ||||||
0% to 10% | 0.24 (−0.08 to 0.57) | 0.25 (−0.08 to 0.57) | 0.23 (−0.10 to 0.57) | 0.65 (0.55 to 0.75) | 0.65 (0.55 to 0.75) | 0.61 (0.51 to 0.71) |
10% to 15% | 1.29 (0.96 to 1.62) | 1.29 (0.96 to 1.62) | 1.26 (0.93 to 1.60) | 0.44 (0.34 to 0.54) | 0.44 (0.34 to 0.55) | 0.41 (0.30 to 0.51) |
Regular hours‡ | ||||||
0% to 10% | 0.19 (0.02 to 0.36) | 0.19 (0.02 to 0.36) | 0.16 (−0.01 to 0.34) | 0.21 (0.16 to 0.26) | 0.21 (0.16 to 0.26) | 0.20 (0.14 to 0.25) |
10% to 15% | 0.69 (0.52 to 0.87) | 0.70 (0.52 to 0.87) | 0.67 (0.49 to 0.85) | 0.17 (0.12 to 0.23) | 0.17 (0.12 to 0.23) | 0.16 (0.10 to 0.22) |
After hours‡ | ||||||
0% to 10% | 0.06 (−0.19 to 0.30) | 0.06 (−0.19 to 0.30) | 0.07 (−0.18 to 0.32) | 0.44 (0.37 to 0.52) | 0.44 (0.37 to 0.52) | 0.41 (0.33 to 0.49) |
10% to 15% | 0.59 (0.35 to 0.84) | 0.59 (0.35 to 0.84) | 0.59 (0.35 to 0.84) | 0.27 (0.18 to 0.35) | 0.27 (0.18 to 0.35) | 0.24 (0.16 to 0.33) |
Urgent ED visits | Less-urgent ED visits | |||||
IPW β (95% CI)† | CBPS β (95% CI)† | Entropy balancing β (95% CI)† | IPW β (95% CI)† | CBPS β (95% CI)† | Entropy balancing β (95% CI)† | |
Any timing | ||||||
0% to 10% | 0.84 (0.66 to 1.02) | 0.84 (0.66 to 1.02) | 0.79 (0.60 to 0.98) | −1.24 (−1.46 to −1.02) | −1.24 (−1.46 to −1.02) | −1.16 (−1.39 to −0.94) |
10% to 15% | 0.87 (0.68 to 1.06) | 0.87 (0.68 to 1.06) | 0.83 (0.63 to 1.02) | −0.02 (−0.24 to 0.18) | −0.02 (−0.24 to 0.18) | 0.03 (−0.18 to 0.24) |
Regular hours‡ | ||||||
0% to 10% | 0.36 (0.26 to 0.46) | 0.36 (0.27 to 0.46) | 0.35 (0.24 to 0.45) | −0.38 (−0.51 to −0.26) | −0.38 (−0.51 to −0.26) | −0.38 (−0.50 to −0.25) |
10% to 15% | 0.39 (0.28 to 0.49) | 0.39 (0.28 to 0.49) | 0.37 (0.26 to 0.47) | 0.13 (0.01 to 0.26) | 0.14 (0.01 to 0.26) | 0.14 (0.02 to 0.26) |
After hours‡ | ||||||
0% to 10% | 0.47 (0.33 to 0.61) | 0.47 (0.33 to 0.61) | 0.44 (0.30 to 0.58) | −0.86 (−1.02 to −0.70) | −0.86 (−1.02 to −0.70) | −0.78 (−0.95 to −0.62) |
10% to 15% | 0.49 (0.34 to 0.63) | 0.49 (0.34 to 0.63) | 0.46 (0.31 to 0.61) | −0.16 (−0.31 to −0.01) | −0.16 (−0.31 to −0.01) | −0.11 (−0.26 to 0.04) |
Note: CBPS = covariate-balancing propensity score weighting, CI = confidence interval, ED = emergency department, IPW = inverse probability weighting.
↵* Controlled for patient characteristics (patient age, low-income status, and comorbidity using aggregated diagnosis group score), and physician characteristics (physician age, physician age-squared, years since graduation, years since graduation-squared, physician sex, international medical graduation status, and group size) as well as the monthly dummy variable.
↵† 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.
↵‡ Regular hours refers to 8 am to 5 pm weekdays; after hours refers to 5 pm to 8 am weekdays, and any time on weekends and statutory holidays.