Table 3. Risk-adjustment model results based off variables that met criteria for stepwise selection (PR0.10 for entry and exit).

Outcome/risk factor	Derivation cohort [2011–2013] (N=7,192), odds ratio (95% CI)			Validation cohort [2014] (N=4,182), odds ratio (95% CI)
	Severe adverse event	Unplanned readmission		Severe adverse event	Unplanned readmission
Demographics
Age		1.01 (1.00–1.02)*
Age Sqr	1.00 (1.00–1.00)			1.00 (1.00–1.00)*	1.00 (1.00–1.00)*
ASA classification
3 or 4	1.33 (1.12–1.57)*	1.19 (1.00–1.42)*		1.22 (0.98–1.53)	1.33 (1.04–1.69)*
Comorbid conditions
BMI (>40)	1.45 (1.14–1.85)*	1.33 (1.02–1.72)*		1.95 (1.45–2.64)*	2.13 (1.55–2.92)*
Bleeding disorder				1.83 (1.00–3.33)*
History of smoking				1.49 (1.16–1.91)*	1.33 (1.01–1.76)*
COPD		1.56 (1.15–2.12)*
Dyspnea with exertion		1.29 (0.99–1.69)			1.50 (1.03–2.18)*
Diabetes mellitus	1.21 (1.00–1.47)*	1.19 (0.97–1.45)*		1.29 (1.01–1.63)
Corticosteroid use					2.03 (1.37–3.00)*
Congestive heart failure				2.93 (1.07–8.07)*
Disseminated cancer	2.42 (1.27–4.59)*			3.93 (1.86–8.29)*	3.26 (1.45–7.29)*
Dialysis-dependent				4.26 (1.39–13.11)	6.22 (2.13–18.21)*
Functional status, partially dependent	1.62 (1.14–2.31)*			1.64 (0.98–2.73)
Laboratory results within 90 days pre–op. (%)
Low WBC count (<4,500/mcL)		1.37 (0.99–1.82)*
High WBC count (>10,000/mcL)	1.63 (1.32–2.02)*	1.43 (1.14–1.79)*
Low hematocrit (<30%)	1.51 (0.93–2.46)			2.04 (1.13–3.68)*
Low platelets (<150,000/mcL)	1.53 (1.14–2.06)*
High INR (>1.1)	1.43 (1.03–1.98)*
Low sodium (<135 mEq/L)		1.35 (0.99–1.83)		1.70 (1.21–2.38)*
High creatinine (>1.3 mg/dL)	1.37 (1.00–1.87)*	1.41 (1.06–1.89)*		1.63 (1.14–2.34)*	1.63 (1.11–2.38)*
High bilirubin (>1.9 mg/dL)	4.09 (1.61–10.37)*	5.05 (2.11–12.08)*		7.14 (1.32–38.70)*
Low albumin (<3.4 g/dL)	1.62 (1.10–2.39)*	2.05 (1.39–3.01)*		2.80 (1.79–4.39)*	2.03 (1.22–3.39)*
Intraoperative variables
Operating time	1.00 (1.00–1.00)*	1.00 (1.00–1.00)*		1.00 (1.00–1.00)*

*, indicates significant P value <0.05.