Design, conduct, and analysis of a multicenter, pharmacogenomic, biomarker study in matched patients with severe sepsis treated with or without drotrecogin Alfa (activated)

Annals of Intensive Care

Table 3 Rationale for selected Mahalanobis distance variables

Baseline characteristic(variable)	Associated with mortality risk only	Associated with DAA treatment selection and mortality risk	Comments
Age		√	Increased age is associated with increased mortality [3]. Age is a variable in APACHE II [19] and SAPS II [26]; also known that DAA typically given to younger patients [18–23]
APACHE II or SAPS II		√	Both are proven predictive mortality scores; DAA typically given to patients with higher scores [18–23]
Cardiovascular organ dysfunction		√	Mortality is higher in patients with septic shock versus sepsis without shock; DAA believed to be particularly effective in patients with shock [27]
Respiratory organ dysfunction	√		Respiratory dysfunction increases mortality [28, 29]
Renal organ dysfunction	√		Renal dysfunction increases mortality [30, 31]
Hematologic organ dysfunction		√	Hematologic dysfunction increases mortality [32, 33]; DAA is particularly effective in patients with coagulopathy disorders (low platelets) [27]
Use of mechanical ventilation	√		Need for mechanical ventilation increases mortality [28, 29]
Medical or surgical status		√	Type of admission is a variable in APACHE II and SAPS II [34, 35]; recent surgery is a relative contraindication for DAA due to increased bleeding risk [7]
Site of primary infection		√	Predicted mortality varies with site of primary infection, but this is mostly a DAA selection bias variable; DAA may be particularly helpful when lung is source of primary infection [36]