Combination ICU Mortality Calculator

APACHE II, SAPS II, and SOFA scores to predict hospital mortality

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Does this patient have severe organ system insufficiency or is immunocompromised? See definitions Severe organ system insufficiency or immunocompromised information

US units
Model Score Est. Mortality
SAPS II 1 53 53%
APACHE II 2 19 32.2% Question
SOFA 3 9 15 - 20%

About This Calculator

This calculator is designed for researchers who are calculating a number of different ICU mortality scores on a single patient. By combining data entry into one form, a researcher will not be required to enter the same variable (such as heart rate or serum sodium) multiple times on multiple online calculators.

For more information about an individual mortality models (such as inclusion/exclusion, variables included, correlation to mortality, etc.), please visit each respective calculators:

Definitions of 'severe organ system insufficiency' and 'immunocompromised'

  • Liver: Biopsy-proven cirrhosis with portal hypertension; episodes of past upper GI bleeding attributed to portal hypertension; or prior episodes of of hepatic failure, encephalopathy, or coma
  • Cardiovascular: New York Heart Association (NYHA) class IV heart failure
  • Respiratory: Chronic restrictive, obstructive, or vascular disease resulting in severe exercise restriction (ie, unable to climb stairs or perform household duties); documented chronic hypoxia, hypercapnia, secondary polycythemia, severe pulmonary hypertension (>40 mmHg); or respirator dependency
  • Renal: Receiving chronic dialysis
  • Immunocompromised: The patient has received therapy that suppresses resistance to infection (eg, immunosuppression, chemotherapy, radiation, long-term or high-dose steroids, or advanced leukemia, lymphoma, or AIDS)

Disadvantage of APACHE II

APACHE II scores are often reported in the literature as a point value, rather than a percent mortality. Given that APACHE II scores are reported in order to describe severity of illness in a population, it may become difficult to accurately compare two heterogeneous groups on the basis of an APACHE II score because predicted mortality is based on ICU admission indication.

As an example, an APACHE II score of 25 points is associated with a predicted mortality rate of 73.6% if admitted for neoplasm, but only 38.9% if admitted for a seizure disorder. While often times clinical trials use APACHE II scores to compare two groups within a trial who often have the same ICU admission indication, this discrepancy limits the applicability of interpreting an APACHE II score in a patient population with a variety of disease states.

Comparison of ICU Mortality Models

There have been a number of studies examining the difference in accuracy between various ICU mortality prediction models. A summary of three prospective, large, multicenter studies is shown below, in addition to the original publications for both SAPS II and APACHE II.

AUC ROC (area under curve, receiver operating characteristic) is a measure of the specificity and sensitivity of a prediction method. AUC ROC is described between 0.5 and 1.0, with an AUC of 1.0 being perfectly sensitive and specific. Generally speaking, an AUC above 0.8 is desirable.

Overall Poor Performance

In two of the trials 4,5 both SAPS II and APACHE II demonstrated a significant value for the Hosmer-Lemeshow goodness-of-fit test (p < 0.001), which is indicative that both models performed poorly despite showing a moderate AUC ROC (eg, there was a significant discrepancy between expected and observed mortality).

As highlighted by the poor results of the goodness-of-fit tests, there are a number of unique patient factors that cannot be accounted for in an ICU mortality model. Despite this fact, both SAPS II and APACHE II are still widely used to describe illness severity in clinical trials.

Citation Enrollment Period # Patients # ICUs Country AUC ROC
Moreno 4 1994 - 1995 982 19 Portgual 0.817 0.787
Livingston 5 1995 - 1996 10,393 22 Scotland 0.843 0.805
Beck 6 1993 - 1996 16,646 17 England 0.852 0.835
SAPS II 1 1991 12,997 137 Multiple 0.860 -
APACHE II 2 1979 - 1982 5,030 13 United States - 0.863

References and Additional Reading

  1. Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study. JAMA. 1993;270(24):2957-63. PMID 8254858.
  2. Knaus WA, Draper EA, Wagner DP. APACHE II: a severity of disease classification system. Crit Care Med. 1985;13(10):818-29. PMID 3928249.
  3. Vincent JL, de Mendonça A, Cantraine F, et al. Use of the SOFA score to assess the incidence of organ dysfunction/failure in intensive care units: results of a multicenter, prospective study. Crit Care Med. 1998;26(11):1793-800. PMID 9824069.
  4. Moreno R, Morais P. Outcome prediction in intensive care: results of a prospective, multicentre, Portuguese study. Intensive Care Med. 1997;23(2):177-86. PMID 9069003.
  5. Livingston BM, MacKirdy FN, Howie JC, et al. Assessment of the performance of five intensive care scoring models within a large Scottish database. Crit Care Med. 2000;28(6):1820-7. PMID 10890627.
  6. Beck DH, Smith GB, Pappachan JV, et al. External validation of the SAPS II, APACHE II and APACHE III prognostic models in South England: a multicentre study. Intensive Care Med. 2003;29(2):249-56. PMID 12536271.


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Updated Nov 10, 2018

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