Table 1.

Univariate logistic analysis of potential predictors for POD in IVPCA patients

Predictors	No delirium, n (%) N=1,573 (97.9)	Delirium, n (%) N=35 (2.1)	Crude odds ratio (95% CI)	P-value
Age groups
60–69 years	767 (98.7)	10 (1.3)	1.0
≥70 years	806 (97.0)	25 (3.0)	2.38 (1.14–4.99)	0.018
Gender
Female	866 (98.1)	17 (1.9)	1.0
Male	707 (97.6)	18 (2.4)	1.30 (0.66–2.54)	0.554
ASA physical status
I, II, III	1,423 (99.2)	27 (1.8)	1.0
IV	150 (95.0)	8 (5.0)	2.81 (1.25–6.30)	<0.001
Hypertension
No	693 (99.0)	15 (2.1)	1.0
Yes	880 (97.8)	20 (2.2)	1.05 (0.53–2.07)	0.887
Diabetes mellitus
No	792 (98.3)	14 (1.7)	1.0
Yes	781 (97.4)	21 (2.6)	1.52 (0.77–3.01)	0.225
Types of surgery
Others (thoracotomy, lower abdomen, breast, head, and neck surgery)	170 (99.4)	1 (0.6)	1.0
Nephrectomy	70 (97.2)	2 (2.8)	4.86 (0.43–54.43)	0.210
Upper abdomen	568 (97.3)	16 (2.7)	4.79 (0.63–36.37)	0.139
Orthopedic surgery	765 (98.0)	16 (2.0)	3.56 (0.47–27.00)	0.335
Duration of surgery
<195 min	1,006 (98.3)	18 (1.7)	1.0
≥195 min	567 (97.1)	17 (2.9)	1.67 (0.86–3.28)	0.127
Duration of anesthesia
<229 min	906 (97.7)	21 (2.3)	1.0
≥229 min	667 (98.0)	14 (2.0)	0.91 (0.46–1.79)	0.775
Total morphine dose/day
≤20 mg/day	1,196 (97.71)	28 (2.29)	1.0
>20 mg/day	377 (98.18)	7 (1.82)	0.79 (0.34–1.83)	0.731
Postoperative nausea/vomiting
No	1,322 (97.6)	32 (2.4)	1.0
Yes	251 (98.8)	3 (1.2)	0.49 (0.15–1.62)	0.236

Notes: Duration of surgery/anesthesia is divided by the mean (195 in surgery, 229 in anesthesia). P<0.05, statistical significance.

Abbreviations: IVPCA, intravenous patient-controlled analgesia; POD, postoperative delirium; CI, confidence interval; ASA, American Society of Anesthesiologists.