Appendix: Definition of Variables

Covariate	Definition
Index infection	Infection present at the time of organ dysfunction or up to 3 days before onset of organ dysfunction
Hospital mortality	Death in hospital before discharge
ICU mortality	Death in ICU
Independent functional status at hospital discharge	“Independent” vs. “other” functional status. “Independent” is defined when the patient is discharged home and independent in activities of daily living. “Other” functional status includes categories of partially dependent, fully dependent, or dead.
Hospital length of stay	Number of consecutive days in current acute care hospital
ICU length of stay	Number of consecutive days in ICU. Only the duration of the first ICU stay during hospitalization is counted.
Age	Age of the patient in years
Gender	Male or female
SAPS II* score	Calculated from the necessary variables provided in the CPI dataset according to the methods of LeGall, et al 1
SAPS II predicted mortality	Calculated from the necessary variables provided in the CPI dataset according to the methods of LeGall, et al 1
APACHE II score	Calculated from the variables provided in the CPI dataset according to the methods of Knaus, et al 2
Origin prior to hospital admission	Admission from the community vs. a health-care associated facility, the latter including another location within the hospital or transfer from another hospital
Previous ICU admission	Previous ICU admission within the same hospitalization
Acute renal failure	Creatinine > 1.5 mg/dL evident < 48 hours before ICU admission and associated with oliguria
CPR within 24 hours of ICU admission	Self-expanatory
Functional status on hospital admission	“Independent” vs. “other” functional status. The “other” category includes partially dependent and fully dependent.
Code status on ICU admission	Full vs. “limited.” The “limited” category included no CPR, limited interventions/ withholding therapy, or withdrawing therapy/ comfort care code status.
Medicine service vs. surgery	Surgical category includes elective and emergent surgical admissions
Index infection	Current infection present at or up to 3 days prior to the time when acute organ dysfunction was detected. At least one of the following conditions must be met: antibiotics started for presumed infection; antibiotics administered for a known active infection (not for antibiotic prophylaxis); purulent drainage from wound or catheter site; radiological evidence of infiltrates and sputum production; white blood cells present in a normally sterile body fluid.
Intra-abdominal infection	Infection in the abdominal compartment and pelvis. Includes peritoneal fluid, abscess drainage, and fluid from surgical drain.
Bloodstream infection	Bloodstream infection not due to vascular access site
Chest infection	Infection of lungs, pleura, pleural fluid, or drainage around chest tube site
CNS infection	Infection of brain, meninges, CSF, spine, or drainage from or around invasive CNS device
Sinus infection	Infection of fluid in cranial or facial sinus cavity
Surgical infection	Infection of any surgical wound site regardless of location
Urinary infection	Infection of kidney, bladder, urethra, drainage around invasive device, or perinephric abscess
Vascular infection	Infection related to invasive vascular catheter
Other infection	Infection of any other known site
Unknown infection	Signs of infection present but unknown site (this category is not chosen if there is a clinically suspected site)
Index organ dysfunction	Organ dysfunction occurring within ± 3 days of a presumed infection
Acute cardiovascular dysfunction	Any one of the following persisting for ≥ 1 hour despite adequate fluid resuscitation: systolic blood pressure (SBP) < 90 mmHg unless known baseline SBP <90 mmHg ; SBP > 40 mmHg below baseline SBP; mean arterial pressure (MAP) < 70mmHg; vasopressor (if dopamine, > 5 mcg/kg/ min) requirement to maintain SBP > 90 or MAP > 70 mmHg
Elevated serum lactate	Serum lactate value above the normal range in combination with acute cardiovascular dysfunction on the same day
Acute respiratory dysfunction	PaO2 / FiO2 ratio ≤ 300 or PEEP requirement > 5 cm H20 in patients with acute lung injury (patients with cardiogenic pulmonary edema are excluded)
Acute renal dysfunction	Creatinine remains increased by > 1 mg/dL after adequate fluid resuscitation or creatinine ≥ 2 mg/dL in the absence of known baseline (patients on chronic dialysis excluded)
Acute hematologic dysfunction	Platelet (plt) count half of the highest value in last 3 days, or plt count <100,000mm3, or PT/PTT >1.5 times control in absence of anticoagulant
Acute hepatic dysfunction	Acute rise in serum total bilirubin to a level > 2 mg/dL
Acute neurological dysfunction	Acutely altered sensorium and all of the following: no known CNS injury, presence of sedation holiday, and Glasgow coma score (GCS) ≤ 12
fresh frozen plasma transfusion	Any transfusion of fresh frozen plasma during the ICU stay
Packed red blood cell (PRBC) transfusion	Any transfusion of PRBCs during the first 21 days of ICU stay
Intravenous nutrition	Any administration of intravenous nutrition during the ICU stay
Stress ulcer prophylaxis	Any administration of stress ulcer prophylaxis during the ICU stay
Hemodialysis catheter	Placement of a hemodialysis catheter during the ICU stay
Deep venous thrombosis (DVT) prophylaxis	Administration of any of the following prophylactic treatments during the ICU stay: unfractionated, low-molecular weight, or synthetic heparin or spontaneous compression devices
Invasive mechanical ventilation	Administration of invasive mechanical ventilation upon ICU admission
Chronic liver disease	Any of the following: biopsy proven cirrhosis and documented portal hypertension; episodes of past upper GI bleeding attributed to portal hypertension; prior episodes of hepatic failure/ encephalopathy/ coma
Chronic cardiovascular disease	New York Heart Association Class IV symptoms and one or more of the following: severe coronary artery disease; severe valvular heart disease; severe cardiomyopathy
Chronic respiratory disease	Any of the following: chronic restrictive, obstructive or vascular disease resulting in severe mobility restriction; respiratory dependency; chronic hypoxia, hypercapnea, secondary polycythemia or severe pulmonary hypertension (>40 mmHg)
Chronic renal disease	A history of chronic renal compromise with most recent creatinine > 2.0 mg/dL
Immunocompromise	Any of the following: AIDS, immunosuppressive drugs, radiation or chemotherapy within 1 year of ICU admission, documented immuno-humoral or cellular immune deficiency state
Active cancer within 5 years	Any of the following in the past 5 years: solid organ tumor, hematological malignancy, lymphoma, or proven metastases
Race	African American / African European / Haitian) vs. “other.” The “other” category includes White / Caucasian, American Indian/ Alaska Native, Australian Aborigine, Asian/ Pacific Islander, Latin/ Hispanic, , other, or unknown.
Payment source	Medicaid insurance (including Medicaid managed care) or self-pay vs. other insurance. The other insurance category includes managed care, commercial/ indemnity insurance, Medicare, Medicare managed care, government insurance, national health service, or other.
Critical care medicine (CCM) management	A critical care medicine physician was responsible for the overall care of the patient for all or a portion of the patient’s ICU stay
Hospital beds	Number of licensed hospital beds
Academic hospital	Academic vs. “other” hospital. The “other” category includes city/ county, state, Veteran’s Administration, community/ for profit, and community/ not for profit.
Medical school	The hospital is the primary teaching hospital of an accredited medical school
CCM fellowship program	The hospital is the primary location of an accredited Critical Care Medicine fellowship
Residency program	The hospital is the primary location of an accredited residency program