Table 4.

Relationship between LOS and all confounding variables for discharged patients

Confounding variables	IV LOS in hour (N=702)	Other than IV LOS in hour (N=484)
Categorical confounders	Median (25th–75th centile)	Median (25th–75th centile)
Gender
Male	9.5 (6.7–15.0)**	8.0 (5.5–12.3)**
Female	11.1 (7.9–16.9)	9.8 (6.1–18.4)
Triage priority
High (1–2)	9.7 (6.7–15.3)**	8.8 (5.8–13.1)
Low (3–5)	10.8 (7.9–17.0)	8.8 (5.8–15.0)
Arrival
Ambulance	10.8 (7.3–16.3)	8.8 (5.7–15.5)
Walk-in	10.0 (7.2–15.7)	8.7 (5.8–13.5)
Trauma injury
Yes	7.1 (4.1–13.0)**	6.4 (4.6–12.7)**
No	10.4 (7.3–15.9)	9.0 (5.9–14.8)
Abdominal pain
Yes	11.3 (7.8–17.5)**	10.5 (5.7–13.4)**
No	9.6 (6.9–14.6)	8.3 (6.9–14.6)
Blood test
Yes	16.4 (10.2–23.6)**	18.5 (11.6–25.0)**
No	10.0 (7.1–15.5)	8.6 (5.8–13.8)
Heart-rate monitoring
Yes	14.6 (10.6–24.4)**	12.7 (9.2–27.8)**
No	9.8 (6.9–15.2)	8.2 (5.7–13.4)
Oxygen support
Yes	13.5 (8.7–23.0)**	10.4 (8.7–23.0)
No	10.0 (7.1–15.4)	8.6 (5.7–14.0)
Isolation
Yes	22.7 (11.3–36.7)**	22.6 (11.7–44.3)**
No	10.0 (7.1–15.7)	8.6 (5.8–13.5)
Time of day of arrival with
Low LOS	9.0 (7.1–10.7)**	8.6 (6.1–10.4)
High LOS	11.1 (7.2–16.9)	8.8 (5.7–15.2)
Continuous confounders	Spearman rank-order correlation	Spearman rank-order correlation
Age	0.18**	0.09*
Crowding	0.06	−0.06
Time to patient care by physician	0.21**	0.19**
Number of examinations (range 0–15)	0.33**	0.29**
Number of specialist consultations (range 0–8)	0.41**	0.44**
Number of doses (range 1–7)	−0.13**	−0.10*
Baseline pain intensity score	−0.06	−0.01

IV, intravenous route of analgesia administration; LOS, length of stay.

*p<0.05; **p<0.01.