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. Author manuscript; available in PMC: 2015 Apr 10.
Published in final edited form as: J Intensive Care Med. 2012 Dec 26;29(2):87–95. doi: 10.1177/0885066612467162

Table 2.

Predictive factors for Post-discharge Infections and Hospitalizations (Unadjusted)

Post-Discharge Infections Post-Discharge Hospitalizations

Rate Ratio 95% CI p-value Rate Ratio 95% CI p-value
Sepsis 5.68 3.21–10.03 < 0.0001 8.06 3.66–17.26 < 0.0001
Age (by Quartile)
 1st Quartile (34–54 years) Ref Ref
 2nd Quartile (55–68 years) 1.57 0.71–3.49 0.26 1.64 0.61–4.43 0.33
 3rd Quartile (69–77 years) 1.11 0.47–2.61 0.8 1.28 0.43–3.79 0.66
 4th Quartile (78–98 years) 2.73 1.27–5.89 0.01 3.35 1.26–8.81 0.02
Race
 White Race Ref Ref
 Black Race 0.81 0.47–1.38 0.43 1.02 0.55–1.88 0.95
 Other Race 0.40 0.17–0.93 0.03 0.33 0.09–1.17 0.09
White Race vs Non-white (ref) 1.44 0.87–2.40 0.16 1.21 0.66–2.21 0.53
From
 From Home Ref Ref
 From Nursing Home 3.11 1.87–5.21 < 0.0001 3.17 1.78–5.66 < 0.0001
 From Other 0.50 0.22–1.16 0.11 0.21 0.05–0.87 0.03
From Nursing Home vs Not (ref) 3.51 2.16–5.71 < 0.0001 3.87 2.19–6.85 < 0.0001
ICU LOS (by Quartile)
 1st Quartile (2 days) Ref Ref
 2nd Quartile (3–4 days) 1.14 0.51–2.53 0.76 1.13 0.42–3.03 0.81
 3rd Quartile (5–8 days) 2.90 1.6–5.24 0.004 2.68 1.11–6.46 0.03
 4th Quartile (9–147 days) 2.11 1.01–4.40 0.04 1.89 0.73–4.88 0.19
Hosp LOS (by Quartile)
 1st Quartile (2–5 days) Ref Ref
 2nd Quartile (6–12 days) 1.11 0.49–2.50 0.8 1.56 0.52–4.70 0.43
 3rd Quartile (13–28 days) 2.46 1.22–4.98 0.01 3.01 1.13–8.05 0.03
 4th Quartile (31–147 days) 3.02 1.42–6.40 0.004 2.97 1.04–8.44 0.04
Cardiac 1.14 0.59–2.23 0.69 1.69 0.76–3.73 0.20
Neurologic 2.00 1.19–3.37 0.009 2.38 1.30–4.35 0.005
Malignancy 0.92 0.46–1.82 0.8 0.76 0.37–1.55 0.45
Diabetes 0.73 0.41–1.30 0.28 0.62 0.34–1.16 0.14
Gastrointestinal 0.57 0.23–1.41 0.22 0.75 0.31–1.83 0.52
Pulmonary 0.77 0.42–1.43 0.41 0.72 0.37–1.41 0.34
Catheter/Foreign Body 4.03 2.54–6.38 < 0.0001 5.02 2.95–8.55 < 0.0001
Renal 0.88 0.52–1.47 0.62 1.12 0.62–2.03 0.71
Prior Infection 2.78 1.63–4.73 0.0002 4.05 2.09–7.84 < 0.0001
Substance Abuse 0.44 0.24–0.82 0.01 0.35 0.15–0.79 0.01
APACHE (by Quartile)
 1st Quartile (8–16) Ref Ref
 2nd Quartile (17–20) 0.85 0.42–1.69 0.63 0.85 0.38–1.90 0.69
 3rd Quartile (21–25) 1.00 0.49–2.07 0.99 1.06 0.46–2.47 0.89
 4th Quartile (26–42) 1.42 0.68–2.95 0.35 0.96 0.40–2.27 0.92
Mechanical Ventilation 0.95 0.49–1.85 0.88 0.91 0.43–1.95 0.81
Pressors 2.13 1.14–3.97 0.02 1.71 0.85–3.42 0.13
Acute renal failure 1.28 0.75–2.18 0.36 0.99 0.54–1.83 0.99
New hemodialysis 1.10 0.34–3.61 0.87 1.30 0.38–4.44 0.68
Albumin (by Quartile)
 1st Quartile (1.1–2.2 g/dL) Ref Ref
 2nd Quartile (2.3–2.7 g/dL) 1.11 0.58–2.13 0.75 0.73 0.34–1.55 0.41
 3rd Quartile (2.8–3.3 g/dL) 0.65 0.34–1.26 0.2 0.59 0.28–1.25 0.17
 4th Quartile (3.4–4.7 g/dL) 0.35 0.14–0.83 0.02 0.31 0.12–0.84 0.02
Albumin (Continuous) 0.52 0.38–0.69 < 0.0001 0.51 0.35–0.75 0.0005
Mean blood sugar (by Quartile)
 1st Quartile (82–116 mg/dL) Ref Ref
 2nd Quartile (117–130 mg/dL) 0.59 0.28–1.22 0.15 0.55 0.24–1.30 0.18
 3rd Quartile (130–165 mg/dL) 0.70 0.34–1.44 0.33 0.64 0.29–1.45 0.29
 4th Quartile (166–528 mg/dL) 0.69 0.37–1.30 0.26 0.56 0.26–1.22 0.15
Lactate (by Quartile)
 1st Quartile (0.5–0.9 mmol/L) Ref Ref
 2nd Quartile (1–1.9 mmol/L) 0.96 0.47–1.95 0.91 1.00 0.41–2.42 1.00
 3rd Quartile (2–3.2 mmol/L) 1.30 0.65–2.61 0.45 0.94 0.42–2.10 0.88
 4th Quartile (3.3–20.6 mmol/L) 1.13 0.51–2.49 0.76 0.87 0.34–2.22 0.77

Predictive factors for post-discharge infections were measured based on univariable and multivariable proportional rates/means models. Risk factors for hospital readmission for infection were calculated based on univariable and multivariable proportional rates/means models.

Variable selection for multivariable models was performed by backward selection based on Wald criteria. ICU = intensive care unit; LOS = length of stay; APACHE = Acute Physiology and Chronic Health Evaluation.