Table 3.

Impact of preoperative variables on the length of stay. Preoperative variables were included in univariate analysis if significant in Table 1, Table 2 and Table 3 and N > 9. Variables were included in the multivariate model if p < 0.2 for univariate analysis.

Variable	Univariate		Multivariate
	RR (CI)	p-Value	aRR (CI)	p-Value
Malnourished	5.09 (3.36–6.81)	<0.001 *	3.49 (1.97–5.02)	<0.001 *
Age	−0.03 (−0.09–0.03)	0.264	−0.01 (−0.06–0.04)	0.740
Female	−0.10 (−1.65–1.46)	0.904	−0.16 (−1.55–1.23)	0.820
Race
NHW	−1.47 (−2.97–0.03)	0.055	REF	REF
NHB	1.61 (−0.37–3.58)	0.110	1.39 (−0.61–3.39)	0.173
Hispanic	0.66 (−1.83–3.15)	0.604	0.34 (−2.17–2.85)	0.793
Asian	1.63 (−1.42–4.68)	0.295	1.54 (−1.56–4.64)	0.330
AIAN	−5.07 (−18.92–8.79)	0.473	−3.93 (−17.67–9.80)	0.574
NHOPI	−2.40 (−14.40–9.61)	0.695	−0.70 (−12.61–11.21)	0.908
BMI	−0.05 (−0.17–0.07)	0.413	-	-
ASA (1–2)	−2.57 (−4.80–−0.35)	0.024 *	REF	REF
ASA (3–4)	2.57 (0.35–4.80)	0.024 *	1.56 (−0.46–3.58)	0.130
Electrolyte abnormality	1.50 (−0.49–3.48)	0.139	0.03 (−1.69–1.75)	0.971
Emergency case	−0.83 (−2.82–1.15)	0.411	-	-
Smoking	−0.86 (−2.76–1.04)	0.374	-	-
Dyspnea	0.69 (−2.31–3.69)	0.652	-	-
Dependent functional status	−0.51 (−3.04–2.01)	0.690	-	-
Bleeding disorder	2.59 (−0.61–5.80)	0.112	1.79 (−0.91–4.49)	0.194
Anemic	2.22 (0.63–3.80)	0.006 *	1.10 (−0.36–2.55)	0.139
RBC transfusion day of surgery	3.01 (1.26–4.76)	0.001 *	2.06 (0.54–3.59)	0.008 *

RR: relative risk; CI: 95% confidence interval; aRR: adjusted relative risk; NHW: non-Hispanic white; NHB: non-Hispanic black; AIAN: American Indian or Alaska native; NHOPI: native Hawaiian or Pacific islander; BMI: body mass index; ASA: American Society of Anesthesiologists classification; RBC: red blood cell. * statistically significant.