Case-mix-adjusted length of stay AND Mortality IN twenty-three finnish ICUs

Electronic supplementary material (ESM)

Table E1. Distribution of disease categories according to APACHE III (8) in the development sample (n= 37 718) and co-efficients for each disease category in models predicting ICU length of stay (ICU LOS) and hospital death.

Disease Category / N of patients (%) / ICU LOS (days; median) / Co-efficient for model predicting ICU LOS / p- value / Co-efficient for model predicting hospital death / Odds ratio (95% Confidence interval)
Nonoperative
Cardiogenic shock / 209 (0.55) / 2.32 / 0.89 / 2.44 (1.75-3.40)
Cardiac arrest / 1811 (4.80) / 2.17 / -0.041 / 0.000 / 0.36 / 1.43 (1.26-1.62)
Aortic aneurysm / 48 (0.13) / 1.35 / 0.74 / 2.09 (0.95-4.64)
Congestive heart failure / 866 (2.30) / 2.10 / 0.041 / 0.000
Cardiomyopathy / 49 (0.13) / 2.00
Peripheral vascular disease / 227 (0.62) / 1.01 / 0.117 / 0.000 / -0.76 / 0.47 (0.23-0.94)
Rhythm disturbance / 496 (1.32) / 1.09 / -0.38 / 0.69 (0.51-0.92)
Unstable angina pectoris / 198 (0.52) / 1.60
Acute myocardial infarction / 862 (2.29) / 1.96 / 0.052 / 0.000 / 0.56 / 1.76 (1.46-2.12)
Acute myocardial infarction and thrombolytic treatment / 557 (1.48) / 1.57
Hypertension / 43 (0.11) / 1.10
Other cardiovascular disease / 316 (0.84) / 1.53
Parasitic pneumonia / 66 (0.17) / 3.82 / 0.208 / 0.000
Aspiration pneumonia / 366 (0.97) / 3.21 / 0.145 / 0.000
Respiratory neoplasm / 54 (0.14) / 1.79 / 1.20 / 3.32 (1.73-6.36)
Respiratory arrest / 118 (0.31) / 2.14 / 0.067 / 0.026
Pulmonary edema / 134 (0.36) / 2.61 / 0.072 / 0.011 / 0.88 / 2.42 (1.49-3.94)
Bacterial pneumonia / 1598 (4.24) / 3.95 / 0.180 / 0.000 / 0.36 / 1.43 (1.22-1.66)
Viral pneumonia / 41 (0.11) / 5.06 / 0.292 / 0.000
Chronic obstructive pulmonary disease / 454 (1.20) / 1.98 / 0.064 / 0.000
Pulmonary embolism / 285 (0.76) / 1.09
Mechanical airway obstruction / 140 (0.37) / 1.91 / 0.065 / 0.019
Asthma / 98 (0.26) / 1.71 / -0.77 / 0.46 (0.20-1.10)
Other respiratory disease / 883 (2.34) / 2.30 / 0.107 / 0.000
Hepatic failure / 230 (0.61) / 2.52 / 0.072 / 0.001 / 0.99 / 2.68 (1.93-3.73)
GI perforation/obstruction / 192 (0.51) / 2.80 / 0.075 / 0.002 / 0.53 / 1.70 (1.14-2.53)
GI bleeding due to varices / 373 (0.99) / 1.42 / -0.074 / 0.000 / 0.89 / 2.44 (1.84-3.23)
GI inflammatory disease / 543 (1.44) / 3.85 / 0.240 / 0.000 / 0.46 / 1.21 (1.19-2.09)
GI bleeding due to ulceration/laceration / 518 (1.37) / 1.28 / -0.050 / 0.001
GI bleeding due to diverticulosis / 42 (0.11) / 1.43
Other GI disease / 530 (1.41) / 1.69 / 0.024 / 0.097 / 0.32 / 1.38 (1.06-1.80)
Intracerebral hemorrhage / 611 (1.62) / 1.70 / 0.85 / 2.34 (1.91-2.87)
Subarachnoid hemorrhage / 557 (1.45) / 1.62 / 0.84 / 2.33 (1.86-2.91)
Stroke / 358 (0.95) / 1.90 / 0.054 / 0.002 / 0.98 / 2.67 (2.07-3.45)
Neurologic infection / 267 (0.71) / 2.54 / 0.154 / 0.000 / -0.70 / 0.50 (0.30-0.82)
Neurologic neoplasm / 53 (0.14) / 0.94
Neuromuscular disease / 82 (0.22) / 4.15 / 0.354 / 0.000
Seizure / 1071 (2.84) / 1.74 / 0.030 / 0.005 / -1.40 / 0.25 (0.185-0.33)
Other neurologic disease / 462 (1.22) / 1.87 / 0.101 / 0.000
Sepsis / 1384 (3.67) / 3.74 / 0.081 / 0.000 / 0.43 / 1.53 (1.32-1.79)
Sepsis of urinary tract origin / 181 (0.48) / 2.66 / 0.057 / 0.019 / -0.45 / 0.64 (0.40-1.00)
Head trauma / 617 (1.64) / 2.17 / 0.111 / 0.000 / 0.27 / 1.31 (1.03-1.67)
Multiple trauma / 500 (1.33) / 1.89 / 0.082 / 0.000
Metabolic coma / 116 (0.31) / 1.97
Diabetic ketoacidosis / 422 (1.12) / 1.05 / -0.058 / 0.000 / -2.26 / 0.10 (0.05-0.24)
Drug overdose / 2582 (6.85) / 0.89 / -0.084 / 0.000 / -1.79 / 0.17 (0.13-0.22)
Other metabolic disease / 651 (1.73) / 1.54 / -0.77 / 0.46 (0.34-0.63)
Coagulopathy / 67 (0.18) / 1.63 / 1.18 / 3.25 (1.66-6.35)
Other hematologic disease / 56 (0.15) / 2.01 / 1.06 / 2.90 (1.42-5.79)
Renal diseases / 539 (1.43) / 1.79
Other medical disease / 1014 (2.69) / 1.13 / -0.64 / 0.53 (0.40-0.70)
Postoperative
Dissecting/ruptured aorta / 420 (1.11) / 2.74 / -0.062 / 0.000
Peripheral vascular disease / 251 (0.67) / 0.97 / -0.140 / 0.000
Elective abdominal aneurysm repair / 786 (2.08) / 1.07 / -0.131 / 0.000 / -1.00 / 0.37 (0.25-0.54)
Peripheral artery bypass craft / 255 (0.68) / 0.95 / -0.075 / 0.000
Carotid endarterectomy / 125 (0.33) / 0.93 / -1.35 / 0.26 (0.06-1.07)
Other cardiovascular diseases / 579 (1.54) / 0.99 / -0.201 / 0.000
Respiratory infection / 152 (0.40) / 1.99
Lung neoplasm / 350 (0.93) / 1.00
Respiratory/neoplasm / 216 (0.57) / 0.99 / -1.43 / 0.24 (0.09-0.65)
Other respiratory disease / 442 (1.17) / 1.22
GI perforation/rupture / 1202 (3.19) / 2.67 / 0.025 / 0.015 / 0.21 / 1.24 (1.04-1.47)
GI inflammatory disease / 296 (0.78) / 3.01 / 0.122 / 0.000 / 0.40 / 1.50 (1.04-2.15)
GI obstruction / 498 (1.32) / 1.76 / -0.071 / 0.000
GI bleeding / 336 (0.89) / 1.53 / -0.091 / 0.000
GI neoplasm / 1092 (2.90) / 1.11 / -0.046 / 0.000
GI cholecystitis/cholangitis / 365 (0.97) / 1.06 / -0.064 / 0.000 / -0.60 / 0.55 (0.37-0.82)
Other GI disease / 745 (1.98) / 1.38 / -0.046 / 0.000
Intracerebral hemorrhage / 426 (1.13) / 1.92
Subdural/epidural hematoma / 604 (1.60) / 1.41 / -0.041 / 0.003 / -0.46 / 0.63 (0.49-0.82)
Subarachnoid hemorrhage / 479 (1.27) / 1.73 / -0.046 / 0.000
Laminectomy/other spinal cord surgery / 74 (0.20) / 0.93 / -18.5 / 0
Craniotomy for neoplasm / 972 (2.58) / 0.91 / -1.42 / 0.24 (0.14-0.43)
Other neurologic diseases / 380 (1.01) / 0.95 / -0.84 / 0.43 (0.24-0.77)
Head trauma / 310 (0.82) / 2.24
Multiple trauma / 558 (1.48) / 1.92 / -1.16 / 0.31 (0.19-0.53)
Renal neoplasm / 186 (0.49) / 0.98 / -0.081 / 0.001
Other renal diseases / 419 (1.11) / 0.94 / -0.061 / 0.000 / -1.04 / 0.35 (0.21-0.61)
Hysterectomy / 93 (0.25) / 0.88 / -0.225 / 0.000
Other gynecologic disease / 352 (0.93) / 0.94 / -0.115 / 0.000 / -1.71 / 0.18 (0.06-0.57)
Hip or extremity fracture / 436 (1.16) / 0.80 / -0.130 / 0.000 / -1.05 / 0.35 (0.22-0.56)
Other orthopedic / 407 (1.08) / 0.90 / -0.077 / 0.000 / -0.61 / 0.54 (0.33-0.89)

Expected ICU LOS and risk of hospital death can be calculated as follows:

Expected ICU LOS (days) =

10 ** (-0.385 - 0.001 * age + 0.005 * SAPS II - 0.0000235*SAPSII2+ 0.021 * single highest TISS score + 0.495 * ICU death

- 0.013 * (SAPSII * ICU death) +0.063*readmission -0.052*other ICUs in the hospital + coefficient for disease category)

Risk of hospital death =

1 / (1 + e ** (5.146 - 0.070 * SAPSII - 0.009 * age- coefficient for disease category)) =

In the equations above, “ICU death” and “other ICUs in the hospital” are dichotomous variables (0,1) and “age” is years. When calculating risk of hospital death, readmissionwere excluded.

Example 1: A 70 year-old patient is admitted to ICU from the emergency department (=nonoperative) with bacterial pneumonia. He/ she receives 30 SAPS II points. The maximum TISS points during the ICU stay are 50. She is discharged from the ICU alive this first ICU admission. There is also another ICU in the same hospital.

Expected ICU LOS (days) =

10 ** (-0.385 - 0.001 * age + 0.005 * SAPS II - 0.0000235*SAPSII2+ 0.021 * single highest TISS score + 0.495 * ICU death

- 0.013 * (SAPSII * ICU death) +0.063*readmission -0.052* other ICUs in the hospital + coefficient for disease category)

= 10 ** (-0.385 - 0.001 * 70 + 0.005 * 30 - 0.0000235 * 302+ 0.021 * 50 + 0.495 * 0 - 0.013 * 30 * 0 + 0.063 * 0-0.052*1+ 0.180)

=10 ** 0.85185 = 7.11

Risk of hospital death =

1 / (1 + e ** (5.146 - 0.070 * SAPSII - 0.009 * age- coefficient for disease category)) =

1 / (1 + e ** (5.146 - 0.070 * 30 - 0.009 * 70- 0.36)) =

1 / (1 + e ** 2.056) =

1 / (1 + 2.71828 ** 2.056) = 0.11

The expected ICU LOS is 7.11 days and the risk of hospital death is 11%.

Example 2: A 40 year-old patient is admitted to ICU from the operating theatre (=operative) with head trauma. This is her/his second ICU admission during this hospital stay. He/ she receives 45 SAPS II points. The maximum TISS points during the ICU stay are 55. She dies in the ICU during this admission. There are no other ICUs in the same hospital.

Expected ICU LOS (days)

= 10 ** (-0.385 - 0.001 * age + 0.005 * SAPS II - 0.0000235*SAPSII2+ 0.021 * single highest TISS score + 0.495 * ICU death

- 0.013 * (SAPSII * ICU death) +0.063*readmission -0.052* other ICUs in the hospital + coefficient for disease category)

= 10 ** (-0.385 - 0.001 * 40 + 0.005 * 45 - 0.0000235*452+ 0.021 * 55 + 0.495 * 1 - 0.013 * (45 * 1) +0.063*1 -0.052* 0)

=10**0.88 = 7.59

Risk of hospital death =

1 / (1 + e ** (5.146 - 0.070 * SAPSII - 0.009 * age- coefficient for disease category)) =

1 / (1 + e ** (5.146 - 0.070 * 45 - 0.009 * 40) =

1 / (1 + e ** 1.636) =

1 / (1 + 2.71828 ** 1.636) = 0.16

The expected ICU LOS is 7.59 days and the risk of hospital death is 16%.

Table E2.Demographic data of the ICUs (validation sample, n=25 586). *n=21 502

ICU / Years of participation / Data collection (manual / electronic) / Hospital Mortality (%) / Existence of other adult ICUs in the hospital (yes /no) / Length of hospital stay after ICU discharge (days); median, interquartile range *) / Proportion of missing data
about length of hospital stay
after ICU discharge (%)
1 / 2000-2003,
2005 / electronic / 11.7 / yes / 6.45, 3.52-11.50 / 2.88
2 / 2000-2005 / electronic / 16.2 / yes / 7.42, 3.43-14.42 / 7.95
3 / 2000-2005 / electronic / 17.3 / no / 6.00, 3.44-12.4 / 5.64
4 / 2000-2005 / electronic / 18.9 / no / 6.43, 3.34-12.47 / 8.43
5 / 2002-2005 / manual / 25.9 / yes / 9.22, 3.32-17.21 / 37.92
6 / 2003-2005 / manual / electronic / 24.1 / yes / 10.21, 4.50-18.42 / 19.55
7 / 2000-2005 / manual / 17.2 / no / 7.30, 3.41-14.01 / 12.06
8 / 2000-2005 / manual / electronic / 13.5 / no / 6.44, 3.56-10.44 / 13.64
9 / 2000-2005 / electronic / 18.8 / no / 6.44, 2.51-12.55 / 6.62
10 / 2004-2005 / manual / electronic / 10.3 / yes / 6.55, 4.33-12.42 / 8.81
11 / 2002-2005 / manual / 13.4 / yes / 5.53, 3.50-11.00 / 6.55
12 / 2000-2005 / manual / 13.9 / no / 6.44, 2.48-12.38 / 10.05
13 / 2000-2005 / manual / 23.1 / no / 6.60, 3.54-14.53 / 5.68
14 / 2000-2005 / electronic / 18.5 / no / 6.44, 2.49-12.38 / 3.94
15 / 2000-2005 / manual / electronic / 14.9 / no / 6.44, 3.42-11.51 / 11.64
16 / 2000-2005 / electronic / 15.2 / no / 6.52, 3.48-12.47 / 12.51
17 / 2000-2005 / manual / 17.6 / no / 6.45, 3.46-12.45 / 9.52
18 / 2000-2005 / manual / 11.7 / no / 5.00, 2.48-9.31 / 11.29
19 / 2000-2005 / manual / 16.6 / no / 5.59, 3.04-11.46 / 7.63
20 / 2000-2005 / manual / electronic / 18.1 / no / 7.53, 4.45-16.44 / 8.0
21 / 2003-2005 / manual / elecronic / 16.6 / no / 6.39, 3.36-13.42 / 5.45
22 / 2000-2005 / manual / electronic / 13.4 / yes / 5.57, 2.55-11.44 / 8.69
23 / 2000-2005 / manual / 24.1 / no / 6.29, 3.16-12.45 / 9.17

ESM Figure.ICU LOS (Days)

Figure E1. Distribution of length of stay in the ICU (ICU LOS) in the development sample (n=37718). Mean 3.3; standard deviation 5.4; median 1.6; maximum 140