eTable 1. Characteristics and outcomes collected for each patient.
Variable
Gender
Race
Age
Acute Physiology Score (APS) Variables on ICU
day 1 and at ICU discharge
Measurement
Male (reference), Female
White (reference), Black, Hispanic, Other
Continuous measure
Weight determined by most abnormal value on ICU day 1 and day
of discharge, sum of weights equals the APS, which ranges 0 to 252.
Variables include pulse rate, mean blood pressure, temperature,
respiratory rate, PaO2: FiO2 ratio (or A-aD02 for intubated patients
with FIO2 > 0.5), hematocrit, white blood cell count, creatinine,
urine output, blood urea nitrogen, sodium, albumin, bilirubin,
glucose, acid base abnormalities, and neurological abnormalities
based on Glasgow Coma Score. Continuous measure.
Chronic health items
AIDS, cirrhosis, hepatic failure, immunosupression, lymphoma,
leukemia or myeloma, metastatic tumor. Not used for elective
surgery patients. Binary variable created for 0 vs. > 0 items.
ICU admission diagnosis
Location prior to ICU admission
116 APACHE IV categories (see reference13)
Operating or recovery room, emergency room, acute care floor
(reference), step-down unit, transfer from another ICU, other
hospital, direct ICU admission from home, and other/unknown
Length of stay before ICU Admission
Square root of time from hospital admission to ICU admission (in
fractional days)
Discharge location
ICU length of stay, first admission
Patient admitted after emergency surgery
Glasgow coma score
Unable to Assess Glasgow coma score due to
sedation/paralysis on days 1 & discharge,
respectively
Ventilated on days 1 & discharge, respectively
Duration of mechanical ventilation
PaO2:FiO2 ratio
Chronic renal failure*
Acute renal failure*
Acute care floor (reference), step-down unit, other
Continuous measured, truncated at 30.0 days.
Yes, No
3 - 15
Yes, No
Yes, No
Continuous measured, truncated at 30.0 days.
Continuous measure
Yes, No
Yes, No
Cardiac dysrhythmia*
Yes, No
Cerebrovascular incident*
Yes, No
Intracranial mass effect*
Yes, No
Gastrointestinal bleeding*
Yes, No
CPR within 24 hours prior to ICU admission
Yes, No
Full code (no DNR restrictions)*
Yes, No
Mortality before hospital discharge
Yes, No
Mortality before ICU discharge
Yes, No
* On admission or within one hour after admission
eTable 2. Characteristics of hospitals & ICUs included in the study
#
# of Hospitals
%
36
Region
NorthEast
7
19.4%
South
7
19.4%
Midwest
16
44.4%
West
6
16.7%
Teaching Status
COTH¥
17
47.2%
Non-COTH Teaching
12
33.3%
Non-Teaching
7
19.4%
Bedsize (median & intra-quartile range)
Number of Participating ICUs at
Each Hospital
406
(307, 600)
1
29
2
3
8.3%
3
4
11.1%
# ICUs
80.6%
47
Type
Cardiac (Coronary)
1
2.1%
Medical
13
27.7%
Mixed Medical-Surgical
28
59.6%
Neurological
1
2.1%
Surgical
4
Beds in ICU (median & intra-quartile range)
¥
COTH = Council of Teaching Hospitals
16
8.5%
(12, 24)
eTable 3. Performance rankings for 47 ICUs based on standardized mortality ratios using
APACHE IVa and NQF. Gray cells indicate agreement between APACHE IVa and NQF.
NQF
SMR < 1.00
SMR = 1.00
SMR > 1.00
SMR < 1.00
3
11
4
SMR = 1.00
4
14
7
APACHE IV
SMR > 1.00
0
0
4
Kappa = 0.126 (p = 0.22)
Bowker’s test of symmetry, asymptotically a Chi-square with 3 degrees of freedom = 14.27
(p=0.003)
eFigure1. SMRs and 99% confidence intervals based on APACHE (blue) and NQF
models (red): ICUs stratified by hospital teaching status.
Council of Teaching
Hospitals (COTH)
Non-COTH- teaching
and non-teaching
lhospital
eFigure2. SMRs and 99% confidence intervals based on APACHE IVa (blue) and
NQF (red) models : Stratified by ICU type
Mixed medicalsurgical units
Specialty
units *
**The specialty units included 13 medical, 4 surgical, 1 cardiac, 1 neurological
ICU
eFigure3. SMRs and 99% confidence intervals based on APACHE IVa (blue) and
NQF (red) models: ICUs stratified by whether mean age was below median (50.762.7) or above median (≥ 62.8)
Mean age below
median
Mean age above
median
eFigure4. SMRs and 99% confidence intervals based on APACHE IVa (blue) and
NQF (red) models: ICUs stratified by whether mean Acute Physiology Score (APS)
was below median (< 40) or above median (≥ 40)
Mean APS below
median
Mean APS above
median
eFigure5. SMRs and 99% confidence intervals based on APACHE IVa (blue) and
NQF (red) models: ICUs stratified by whether percentage on patients placed on
mechanical ventilation was below median (≤ 35%) or above median (> 35%)
≤ 35% of patients
on mechanical
ventilation
> 35% of patients
on mechanical
ventilation
eFigure 6. Smoothed distribution of standardized mortality ratios (SMR) for 47
ICUs based on APACHE (blue) and NQF (red) prognostic after recalibration of
both models
12
APACHE
10
NQF
8
6
4
2
0
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Standardized Mortality Ratio
Black dots indicate median SMR for each predictive model.
1.8
2
2.2
2.4
eFigure 7. Standardized mortality ratio (SMR) and 99% confidence intervals for 47
ICUs based on APACHE IVa (blue lines) and NQF (red lines): Results after
recalibration of both models.