Table 1

Characteristics of study patients

OverallBoarding <14 hoursBoarding ≥14 hoursSMD for boarding
n22 44714 3578 029
Patient characteristics
 Age (years) (IQR)47 (32, 65)49 (33, 66)45 (30, 63)0.117
 Male sex (%)12 127 (54)7688 (54)4406 (55)0.027
 Admissions in previous year (%)0.0 (0.0, 0.0)0.0 (0.0, 0.0)0.0 (0.0, 0.0)0.037
 No fixed address (%)1688 (7.5)1017 (7.1)666 (8.3)0.045
 Family MD (%)14 672 (83.4)9422 (84.1)5206 (82.2)0.052
Primary psychiatric diagnosis0.176
 Anxiety (%)446 (2.0)321 (2.2)124 (1.5)
 Bipolar (%)1251 (5.6)744 (5.2)505 (6.3)
 Conduct (%)103 (0.5)58 (0.4)45 (0.6)
 Depression (%)2176 (9.7)1500 (10.4)671 (8.4)
 Dissociative (%)109 (0.5)71 (0.5)38 (0.5)
 Eating (%)73 (0.3)57 (0.4)16 (0.2)
 Neurocognitive (%)4222 (18.8)2783 (19.4)1434 (17.9)
 Neurodevelopmental (%)132 (0.6)67 (0.5)65 (0.8)
 Obsessive (%)68 (0.3)45 (0.3)23 (0.3)
 Other (%)159 (0.7)99 (0.7)59 (0.7)
 Personality (%)608 (2.7)350 (2.4)250 (3.1)
 Psychosis (%)3803 (16.9)2296 (16.0)1491 (18.6)
 Somatic (%)85 (0.4)54 (0.4)31 (0.4)
 Substance (%)6614 (29.5)4406 (30.7)2198 (27.4)
 Trauma (%)2594 (11.6)1505 (10.5)1076 (13.4)
 Secondary substance use (%)5428 (24.2)3311 (23.1)2103 (26.2)0.073
 Alcohol (%)*6049 (26.9)4123 (28.7)1916 (23.9)0.110
 Opioids (%)*672 (3.0)395 (2.8)276 (3.4)0.040
 Cannabinoids (%)*1549 (6.9)849 (5.9)693 (8.6)0.105
 Sedatives (%)*254 (1.1)174 (1.2)79 (1.0)0.022
 Cocaine (%)*718 (3.2)413 (2.9)305 (3.8)0.051
 Stimulant (%)*1152 (5.1)595 (4.1)555 (6.9)0.121
 Hallucinogen (%)*35 (0.2)23 (0.2)12 (0.1)0.003
Demographic characteristics
 Arrival means0.136
 No ambulance (%)11 185 (49.8)7065 (49.2)4092 (51.0)
 Air ambulance (%)21 (0.1)14 (0.1)7 (0.1)
 Ground ambulance (%)10 385 (46.3)6853 (47.7)3499 (43.6)
 Police (%)856 (3.8)425 (3.0)431 (5.4)
ED
 CTAS score (IQR)2(2,3)2(2,3)2(2,3)0.038
 Antipsychotic used (%)5431 (24.2)1940 (13.5)3490 (43.5)0.704
 Sedative used (%)9188 (40.9)4799 (33.4)4383 (54.6)0.436
 Restraints used (%)3577 (15.9)2091 (14.6)1477 (18.4)0.103
 Mental health form (%)6254 (27.9)3408 (23.7)2812 (35.0)0.250
 High observation bed (%)1607 (7.2)496 (3.5)1111 (13.8)0.376
 MD assessment to admit (hours) (IQR)5.2 (3.5, 7.9)5.2 (3.5, 8.0)5.2 (3.5, 7.7)0.019
 Boarding time (hours) (IQR)6.5 (1.9, 18.8)2.5 (1.4, 5.9)23 (18, 38)1.887
 Total ED time (hours) (IQR)16.9 (8.6, 26.4)10.2 (6.8, 16.2)31 (25, 46)1.787
Primary outcome
 Hospital length of stay (days) (IQR)8.4 (3.5, 25)8.6 (3.5, 25)8.1 (3.8, 26)0.025
  • SMD comparing differences between ≥14 hours and <14 hours boarding time.

  • *Primary or secondary substance use disorders

  • CTAS, Canadian Triage Acuity Scale, 1 is most urgent, 5 is least urgent; ED, emergency department; SMD, standardised mean difference.