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SAPS 3 predicted hospital mortality

Convert a SAPS 3 admission score into predicted hospital mortality (general or Central/Western Europe equation)

Sources last checked: 2026-10-13

SAPS 3 predicted hospital mortality

Convert a SAPS 3 admission score into predicted hospital mortality (general or Central/Western Europe equation)

Equation
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A predicted probability describes groups of patients for case-mix adjustment and standardised mortality ratios (observed/expected); it is not an individual prognosis and must not be used alone to limit treatment. In the derivation data the general equation overestimated mortality in Central/Western Europe (O/E 0.84), which is why the regional equation exists. Calibration drifts over time — recalibrate locally for benchmarking.

Source: Moreno RP, Metnitz PGH, Almeida E et al.; SAPS 3 Investigators. SAPS 3 — From evaluation of the patient to evaluation of the intensive care unit. Part 2: Development of a prognostic model for hospital mortality at ICU admission. Intensive Care Med 2005;31(10):1345-1355.Open

What is the SAPS 3 predicted hospital mortality?

This calculator converts a SAPS 3 admission score into a predicted probability of death before hospital discharge. Moreno, Metnitz and the SAPS 3 investigators published a global logistic equation and seven customised regional equations, including one for Central and Western Europe, which covers Austria (Intensive Care Med 2005). The predicted mortality is mainly used to compute observed-to-expected mortality ratios.

When to use it

  • Benchmarking an ICU: sum predicted deaths over all admissions and compare with observed deaths.
  • Choosing between the global and Central/Western Europe equation for Austrian or German ICUs.
  • Teaching how severity scores translate into probabilities.

When not to use it

  • To predict the outcome of a single patient or to justify limiting treatment.
  • For patients under 16 years or populations very different from the SAPS 3 cohort (e.g. burns, cardiac surgery-only units) without local validation.

How it is calculated

General: logit = −32.6659 + ln(SAPS 3 + 20.5958) × 7.3068 Central/Western Europe: logit = −36.0877 + ln(SAPS 3 + 22.2655) × 7.9867 Predicted hospital mortality = e^logit / (1 + e^logit)

Clinical pearls and limitations

  • A predicted probability describes groups of patients for case-mix adjustment and standardised mortality ratios (observed/expected); it is not an individual prognosis and must not be used alone to limit treatment. In the derivation data the general equation overestimated mortality in Central/Western Europe (O/E 0.84), which is why the regional equation exists. Calibration drifts over time — recalibrate locally for benchmarking.
  • The global equation overestimated mortality in Central/Western Europe in the original data (O/E 0.84); the regional equation corrected this.
  • A score of 48 (cohort median) corresponds to about 14.5 % (global) or 10.7 % (Central/Western Europe).
  • The curve is steep between 50 and 80 points — small scoring errors change the predicted risk considerably.
  • Calibration drifts as ICU care improves; benchmarking projects such as ASDI recalibrate periodically.

Frequently asked questions

How do you calculate mortality from SAPS 3?

logit = −32.6659 + ln(score + 20.5958) × 7.3068, then probability = e^logit / (1 + e^logit). The Central/Western Europe equation uses −36.0877, 22.2655 and 7.9867.

Which SAPS 3 equation should be used in Austria?

Austria belongs to the Central/Western Europe region of the original study, so the customised equation for that region is the closer fit; for international comparison the global equation is used.

What SAPS 3 score means 50 % mortality?

With the global equation about 67 points; with the Central/Western Europe equation about 70 points.

Evidence and guidelines

  1. Primary source: Moreno RP, Metnitz PGH, Almeida E et al.; SAPS 3 Investigators. SAPS 3 — From evaluation of the patient to evaluation of the intensive care unit. Part 2: Development of a prognostic model for hospital mortality at ICU admission. Intensive Care Med 2005;31(10):1345-1355.
  2. Moreno 2005, Part 2 — general equation (Results) and customised regional equations (Table 5), PMC1315315.
  3. BMASGPK. Handbuch zur Dokumentation in landesgesundheitsfondsfinanzierten Krankenanstalten — Anhang 1: Aufbau und Inhalt der Datenmeldungen 2025 (SP3), Kap. 2.4 Intensivdokumentation (Satzart I11 SAPS3-Daten, I12 TISS-A-Daten).

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For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.