Table 3: Univariate and multivariate regression anaylsis for 30-day readmission.

Odds ratios (95% CI) for 30-day readmission
UnivariateMultivariate

White blood cell count (in 1,000's, mm3)
 <6.0ReferenceReference
 6.0–7.90.93 (0.64, 1.33)0.96 (0.65, 1.41)
 8.0–9.90.86 (0.58, 1.29)0.91 (0.59, 1.39)
 10.0–12.01.34 (0.84, 2.14)1.42 (0.86, 2.34)
 >12.01.73 (1.03, 2.93)1.81 (1.03, 3.17)
Other risk factors
 Single-vessel disease1.77 (1.28, 2.46)1.73 (1.24, 2.43)
 Two-vessel disease1.48 (1.04, 2.10)1.43 (1.00, 2.06)
 On-pump surgery2.43 (1.31, 4.54)1.85 (0.98, 3.52)
 Nadir hematocrit on bypass <201.55 (1.10, 2.17)1.39 (0.96, 2.00)
 Three or more packed red blood cells1.86 (1.34, 2.56)1.52 (1.07, 2.18)
 Mediastinitis7.58 (2.64, 21.79)5.81 (1.87, 18.08)
 Acute kidney injury2.21 (1.70, 2.87)2.03 (1.53, 2.68)
Model parameters
 Hosmer-Lemeshow , value = 10.94, value = 0.2
 ROC0.66

WBC: white blood cell; SD: standard deviation of the log-transform of WBC count; ROC: area under the receiver operating characteristic curve.