Table 4.

Sensitivity Analyses: Multivariable logistic regression model of adjusted odds ratios for being assigned an ICD-9 specific code for severe sepsis or septic shock (995.92 and 785.52) where each candidate variable was forced into the model.

Complete Model (n=1721)*	Adjusted Odds Ratio (95% CI)	p-value
Gender (male)	0.74 (0.56 – 0.98)	0.04
Apache II Score (baseline) **	1.06 (1.04 – 1.09)	<0.001
Presence of Shock **	2.94 (2.16 – 4.00)	<0.001
Serum Lactate **	1.13 (1.07 – 1.18)	<0.001
Etiology of Sepsis:
Bacteremia	1.73 (1.19 – 2.53)	0.004
ICU Admission	4.86 (3.38 – 7.00)	<0.001
Time (year) **	1.17 (1.04 – 1.30)	0.006
Sensitivity Analysis †	Adjusted Odds Ratio (95% CI)	p-value
Gender (male)	0.77 (0.59 – 1.00)	0.052
Apache II Score (baseline) **	1.06 (1.04 – 1.08)	<0.001
Presence of Shock **	3.02 (2.23 – 4.09)	<0.001
Serum Lactate **	1.14 (1.09 – 1.19)	<0.001
Etiology of Sepsis:
Bacteremia	1.59 (1.11 – 2.28)	0.01
ICU Admission	4.44 (3.12 – 6.32)	<0.001
Time (year)	1.20 (1.09 – 1.33)	<0.001

^*Age, systolic blood pressure, and admission type (medical vs. surgical) were found to be collinear with Apache II and were therefore not included in the complete model. The remaining variables included in the model (race, comorbidities, and other sites of infection) were not significantly associated with being assigned an ICD9 code for severe sepsis or septic shock.

^**For each 1-unit increase in illness severity measure, serum lactate, or time in years. Shock was defined as systolic blood pressure less than 90 mm Hg after fluid resuscitation (1500 mL) or use of vasoactive agents (13–14).

^†In the sensitivity analyses, a more parsimonious model was created wherein variables that were not significantly associated with being assigned an ICD-9 specific code for severe sepsis or septic shock were removed.