Clinical calculator
Elixhauser Calculator
Elixhauser Comorbidity Score (van Walraven weights)
The Elixhauser comorbidity score applies the van Walraven point weights to 30 comorbidities, giving each a whole-number weight from −7 to +12 so that their sum predicts in-hospital death from hospital diagnosis codes — and in one large national inpatient dataset it discriminated slightly better than the Charlson index.
What the Elixhauser score means
Elixhauser totals run from -19 to 89, where a lower score is better. No severity bands are shown because no cut-offs have been published that we can verify — read the total against the source studies and your own protocol, as described below.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Each of 30 Elixhauser comorbidities that is present contributes its van Walraven weight, and the weights are added. Positive weights: congestive heart failure 7, cardiac arrhythmias 5, pulmonary circulation disorders 4, peripheral vascular disorders 2, paralysis 7, other neurological disorders 6, chronic pulmonary disease 3, renal failure 5, liver disease 11, coagulopathy 3, weight loss 6, fluid and electrolyte disorders 5, lymphoma 9, metastatic cancer 12 and solid tumour without metastasis 4. Negative weights: valvular disease −1, obesity −4, blood loss anaemia −2, deficiency anaemias −2, drug abuse −7 and depression −3. Zero weight: hypertension, uncomplicated and complicated diabetes, hypothyroidism, peptic ulcer disease, HIV/AIDS, rheumatoid arthritis and collagen vascular disease, alcohol abuse and psychoses. The theoretical range is −19 to 89, though real patients cluster far nearer zero. A higher total predicts a higher risk of in-hospital death. No severity bands are published with the system, so none are shown here.
Missing data
The score is defined over diagnosis codes, where an absent code means the condition is not recorded. The calculator above counts an unmarked comorbidity as absent and says how many were left unmarked.
Instrument profile
- Developer
- Anne Elixhauser and colleagues (comorbidity measures); Carl van Walraven and colleagues (point system)
- Institution
- Agency for Healthcare Research and Quality, United States; Ottawa Hospital Research Institute, Canada
- First published
- 2009
- Custodian
- No licensing body; the weights are published in the open literature
- Items
- 21
- Response format
- Present or absent for each of 21 weighted comorbidities
- Score range
- -19 to 89
- Direction
- Lower score = better
- Recall period
- Comorbidities recorded at the index admission
- Completion time
- About 3 minutes
- Age range
- Adults
- Regions
- General Health
- Conditions
- Pre-operative assessment, Perioperative risk, Comorbidity, Multimorbidity
- Procedures
- Total hip arthroplasty, Total knee arthroplasty, Hip fracture surgery, Spinal fusion
- Languages
- English
- Validity
- In a 2021 analysis of all Swiss general-hospital inpatients between 2012 and 2017, a model adding the van Walraven-weighted Elixhauser score to age, sex and hospital type predicted in-hospital mortality with a c-statistic of 0.863, against 0.850 for the Charlson-weighted model and 0.757 for the base model alone.
- Reliability
- Not applicable: a comorbidity score describes the patient at admission and is not meant to track change.
When to use the Elixhauser
Well suited to
- Adjusting for comorbidity in administrative-database or registry studies where hospital diagnosis codes are available — the setting the weights were derived and tested in.
- Choosing a comorbidity adjuster for in-hospital mortality, where a large national comparison found the Elixhauser system discriminated slightly better than the Charlson index.
Limitations and poor fits
- Counselling an individual patient about their prognosis. The weights describe association in a derivation database, not what will happen to a person.
- Estimating long-term survival: the outcome was in-hospital death. The Charlson index was built for longer-term survival.
- Reading a negative total, or a negative weight, as protective.
- Fitness for anaesthesia — use the ASA physical status class, which answers that question directly.
Elixhauser compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| CCI | 17 | 0–37 | The Charlson Comorbidity Index is a weighted checklist of 16 comorbid conditions that produces a comorbidity score of 0 to 33, to which up to 4 points are added for age, and which estimates 10-year survival at roughly 98% for a total of 0, 90% for 2, 53% for 4 and 21% for 5. |
| ASA | 2 | 1–6 | The ASA Physical Status Classification grades a patient’s pre-operative systemic health from I, a normal healthy patient, to VI, a declared brain-dead organ donor, with an E modifier added for emergency procedures. |
| Caprini | 37 | 0–84 | The Caprini Risk Assessment Model estimates the risk of venous thromboembolism in a surgical patient by adding risk factors weighted 1, 2, 3 or 5 points — with elective lower limb arthroplasty, a hip, pelvis or leg fracture, stroke and acute spinal cord injury each worth 5 — to give a total that hospital protocols then map to a prophylaxis level. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
A set of published comorbidity definitions and integer weights, not a copyrightable questionnaire. No licence is required to apply them. We have reproduced the weights from the 2009 derivation as tabulated in an open-access 2021 paper.
References
- van Walraven C, Austin PC, Jennings A, Quan H, Forster AJ. A modification of the Elixhauser comorbidity measures into a point system for hospital death using administrative data. Medical Care. 2009.
- Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Medical Care. 1998.
- Sharma N, et al.. Comparing Charlson and Elixhauser comorbidity indices with different weightings to predict in-hospital mortality: an analysis of national inpatient data. BMC Health Services Research. 2021.doi:10.1186/s12913-020-05999-5
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.