Table 1.

CT use and sociodemographic and ED presentation characteristics of ED episodes

ED episode characteristics		Total (n=1 666 884)	% of ED episodes
Outcome	Any CT	118 589	7.1
	Head CT*	80 772	4.9
	Abdomen pelvis CT*	22 673	1.4
	Spine CT* (cervical/lumbar/thoracic)	15 634	0.9
	Chest CT*	10 738	0.6
	Face CT*	3689	0.2
	Neck CT*	3001	0.2
	Extremity CT*	2626	0.2
Sociodemographic characteristics
Sex	Male	831 455	49.9
Age (years)	18–44	808 472	48.5
	45–64	392 855	23.6
	65–74	159 914	9.6
	75+	305 643	18.3
Socioeconomic index of relative disadvantage	Least disadvantaged	567 971	34.1
	Less disadvantaged	325 040	19.5
	Moderate disadvantage	372 434	22.3
	High disadvantage	220 608	13.2
	Highest disadvantage	158 439	9.5
Remoteness index	Highly accessible (major city)	1 572 748	94.4
	Accessible	33 442	2.0
	Moderately accessible	23 472	1.4
	Remote/very remote	21 727	1.3
ED presentation characteristics
Triage code	Resuscitation	30 429	1.8
	Emergency	315 786	18.9
	Urgent	600 942	36.1
	Semiurgent	587 095	35.2
	Non urgent	132 632	8.0
Arrival	Ambulance/air	651 401	39.1
	Other	1 015 483	60.9
Weekend or public holiday	Weekday	1 112 724	66.8
	Weekend/public holiday	554 160	33.2
Main symptom category	Pain	509 133	30.5
	Injury	322 138	19.3
	Neurological	157 222	9.4
	Respiratory	97 453	5.9
	Gastrointestinal	85 958	5.2
	Cardiovascular	44 515	2.7
	Other	450 465	27.0
Presentation time	09:00–17:00	673 620	40.4
	17:00–00:00	530 926	31.9
	00:00–09:00	462 338	27.7

*Not mutually exclusive.

ED, emergency department.