Table 6.

Results of the multivariate logistic regression

Variable	Univariate analysis p-value	Multivariate analysis OR (95% CI)
Gender	0.0026	0.78 (0.56–1.09)
ASA III–IV	<0.0001	2.74 * (1.93–3.93)
Age >75 yr	0.027	1.33 (0.94–1.89)
>3 Levels	<0.0001	1.94 * (1.28–2.96)
Revision surgery	0.029	1.05 (0.68–1.63)
Procedures
PSIF only	0.0058	0.57 (0.26–1.32)
PSIF + decompression	<0.0001	0.63 (0.28–1.47)
PSIF + PLIF/TLIF	<0.0001	0.39 (0.16–0.94)
Reason for surgery
Degenerative	<0.0001	1.02 (0.59–1.76)
Spinal deformity	<0.0001	7.75 (3.85–16.06)
Postsurgical complications	0.007	0.57 (0.29–1.09)
Spondylodiscitis	<0.0001	2.47 (1.48–4.14)
Vertebral level
Cervical	0.016	3.29 (1.49–7.24)
Cervical-thoracic	<0.0001	8.86 (3.57–25.45)
Thoracic	0.0021	1.35 (0.83–2.19)
Lumbar	0.0001	0.76 (0.44–1.31)
Lumbar-sacral	0.0003	1.04 (0.57–1.91)
Thoracic-sacral	0.0004	4.18 (1.37–13.31)

The initial identification of potential risk factors was assessed using analysis with chi-square and Fisher’s exact test. Afterwards, multivariate logistic regression was conducted for factors with p<0.1 (middle column) from the initial, univariate analysis. The multiple logistic regression was then performed to identify potential risk factors leading to an intensive care unit admission (right column). Statistically significant results are marked in bold.

OR, odds ratio; CI, confidence interval; ASA, American Society of Anesthesiologists; PSIF, posterior spinal instrumentation and fusion; TLIF, transforaminal interbody fusion.