Table 2.

Multiple logistic regression analysis of the 5161^* (randomized to ondansetron, dexamethasone, droperidol, and propofol) and 4086 patients (randomized to all six interventions)

	5161 Patients			4086 Patients
	Odds ratio**	95% CI	P	Odds ratio**	95% CI	P
Ondansetron	0.56	(0.50, 0.64)	<0.001	0.56	(0.48, 0.65)	<0.001
Dexamethasone	0.57	(0.50, 0.65)	<0.001	0.57	(0.49, 0.66)	<0.001
Droperidol	0.58	(0.51, 0.67)	<0.001	0.56	(0.48, 0.66)	<0.001
Propofol	0.69	(0.60, 0.79)	<0.001	0.71	(0.61, 0.83)	<0.001
Carrier gas
Nitrogen (30%O2)	0.81	(0.70, 0.93)	0.003	0.83	(0.72, 0.97)	0.02
Nitrogen (80%O2)	0.99	(0.70, 1.40)	0.96
Remifentanil	0.96	(0.84, 1.10)	0.56	0.94	(0.81, 1.09)	0.39
Female	3.13	(2.33, 4.20)	<0.001	2.87	(2.08, 3.95)	<0.001
Male by droperidol interaction	1.85	(1.26, 2.72)	0.002	1.97	(1.29, 3.00)	0.002
Non-smoking	1.57	(1.32, 1.87)	<0.001	1.57	(1.29, 1.91)	<0.001
History of PONV or motion sickness	1.70	(1.49, 1.95)	<0.001	1.80	(1.54, 2.09)	<0.001
Operations
Hernia repair	1.04	(0.65, 1.67)	0.87	1.08	(0.66, 1.78)	0.75
Cholecystectomy	1.49	(1.08, 2.06)	0.015	1.44	(1.01, 2.05)	0.04
Hysterectomy	1.78	(1.35, 2.35)	<0.001	1.94	(1.43, 2.63)	<0.001
Thyroid	1.22	(0.86, 1.72)	0.27	1.23	(0.85, 1.78)	0.27
Breast	0.74	(0.48, 1.17)	0.20	0.76	(0.46, 1,24)	0.27
Orthopedic surgery	0.91	(0.67, 1.24)	0.55	0.91	(0.65, 1.29)	0.60
Head and neck	1.08	(0.71, 1.65)	0.72	0.88	(0.55, 1.42)	0.61
Other gynecologic	0.91	(0.69, 1.19)	0.48	0.98	(0.73, 1.32)	0.91
Duration of anesthesia (per h)	1.20	(1.12, 1.28)	<0.001	1.15	(1.06, 1.24)	0.001
Postoperative opioids	2.14	(1.75, 2.61)	<0.001	2.01	(1.59, 2.53)	<0.001

^*Corrected for the center as a potentially confounding factor.

^**Odds ratio describe the effects of the interventions or presence of covariates compared to those where the intervention or covariate is absent.