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Table 6 The association between day of the week of death and inpatient stay. Models are presented with no adjustment, adjusted for sex, and adjusted for age and sex; 1430 days of interest, 4,239,788 bed days, 13,461 inpatient deaths

From: The association between the day of the week of milestones in the care pathway of patients with hip fracture and 30-day mortality: findings from a prospective national registry – The National Hip Fracture Database of England and Wales

   Stratification 1 = No stratification 2 = Stratified by sex 3 = Stratified by age and sex
Seasonal Model Parametrisation IRR (95% CI) P IRR (95% CI) P IRR (95% CI) P
Elapsed month Day of the week Sunday 1    1    1   
Monday 1.033 (0.969, 1.100) 0.322 1.037 (0.974, 1.104) 0.253 1.036 (0.973, 1.104) 0.267
Tuesday 1.036 (0.972, 1.104) 0.273 1.036 (0.973, 1.102) 0.273 1.035 (0.971, 1.103) 0.289
Wednesday 1.108 (1.041, 1.180) 0.001 1.111 (1.045, 1.182) 0.001 1.110 (1.043, 1.182) 0.001
Thursday 1.041 (0.977, 1.109) 0.220 1.043 (0.979, 1.110) 0.192 1.042 (0.978, 1.110) 0.203
Friday 1.047 (0.983, 1.116) 0.153 1.049 (0.985, 1.116) 0.136 1.048 (0.984, 1.117) 0.144
Saturday 0.988 (0.927, 1.054) 0.716 0.991 (0.930, 1.056) 0.780 0.991 (0.930, 1.057) 0.791
Weekend Weekday 1    1    1   
Weekend day 0.944 (0.909, 0.980) 0.003 0.944 (0.909, 0.979) 0.002 0.944 (0.909, 0.981) 0.003
Restricted cubic spline Day of the week Sunday 1    1    1   
Monday 1.033 (0.969, 1.100) 0.323 1.037 (0.974, 1.103) 0.257 1.036 (0.973, 1.104) 0.273
Tuesday 1.034 (0.970, 1.101) 0.306 1.035 (0.972, 1.101) 0.284 1.034 (0.971, 1.101) 0.302
Wednesday 1.103 (1.037, 1.174) 0.002 1.107 (1.041, 1.177) 0.001 1.106 (1.040, 1.177) 0.001
Thursday 1.037 (0.974, 1.105) 0.257 1.040 (0.977, 1.107) 0.219 1.039 (0.976, 1.107) 0.231
Friday 1.044 (0.980, 1.112) 0.187 1.045 (0.982, 1.112) 0.166 1.045 (0.981, 1.113) 0.175
Saturday 0.986 (0.925, 1.052) 0.673 0.990 (0.929, 1.054) 0.744 0.990 (0.928, 1.055) 0.756
Weekend Weekday 1    1    1   
Weekend day 0.946 (0.911, 0.982) 0.004 0.945 (0.911, 0.981) 0.003 0.946 (0.911, 0.982) 0.004
  1. There was no significant evidence of an interaction between stratification variables and day of the week parameterisation (likelihood ratio test, P > 0.1), IRR = Incidence Rate Ratio, CI = Confidence Interval. Omnibus Wald test of day of the week, Elapsed Month seasonal specification: (No stratification) P = 0.0128; (Stratified by sex) P = 0.0096; (Stratified by age and sex) P = 0.0125. Omnibus Wald test of day of the week, Restricted Cubic Spline seasonal specification: (No stratification) P = 0.020; (Stratified by sex) P = 0.013; (Stratified by age and sex) P = 0.017. Omnibus Wald test for MTWTF day of inpatient stay are equal to one another, Elapsed Month seasonal specification (No stratification) P = 0.13, (Stratified by sex) P = 0.12, (Stratified by age and sex) P = 0.13, Omnibus Wald test for MTWTF day of inpatient stay are equal to one another, Restricted Cubic Spline seasonal specification (No stratification) P = 0.17, (Stratified by sex) P = 0.14, (Stratified by age and sex) P = 0.15