SINBAD Score for Diabetic Foot Ulcers
SINBAD Score for Diabetic Foot Ulcers
Six binary observations — Site, Ischaemia, Neuropathy, Bacterial infection, Area, Depth — each worth one point, total 0 to 6. The system the IWGDF recommends for communication between professionals and for audit.
SINBAD score
6 items → 0–6Forefoot (0); reduced pedal flow (1); protective sensation lost (1); no infection (0); ulcer 1 cm² or more (1); confined to skin and subcutaneous tissue (0)
Scoring
Total 0–6, every item worth exactly one point
- every item is one point
- there is no weighting at all. That is the design: SINBAD was published by Ince and colleagues in Diabetes Care in 2008 as a simplification of the earlier S(AD)SAD system, and its value is that six bedside observations can be recorded identically in any clinic in the world without equipment
- the six letters
- Site, Ischaemia, Neuropathy, Bacterial infection, Area, Depth. Site is forefoot against midfoot or hindfoot; ischaemia is intact pedal flow with at least one palpable pulse against clinical evidence of reduced flow; neuropathy is protective sensation intact against lost; area is under 1 cm² against 1 cm² or more; depth is skin and subcutaneous tissue against muscle, tendon or deeper
- what the IWGDF says about the alternatives
- the 2023 guideline is unusually direct. Of Wagner’s grades it states that “our group considered this classification to have a poor clinical discrimination” and that it has “insufficient detail when compared with SINBAD”, and it lists “DIAFORA, UTWCS and Wagner” as “not selected to be applied for clinical use or audits”. WIfI gets a CONDITIONAL recommendation for communication and a recommendation for stratifying healing likelihood and amputation risk where the ankle and toe pressures are available
- no strata, and that is why there are no bands here
- the IWGDF recommends the score for communication and audit and publishes no mild/moderate/severe banding for the total. The per-score outcomes printed below come from one 120-patient prospective cohort in International Surgery Journal, which is a description of that cohort and not a validated prediction rule
- the cohort’s own contradiction
- that paper gives the healing rate at a SINBAD of 6 as 1.1 per cent in one table while its counts give 2 healed of 22 patients, which is 9.1 per cent. Both figures are printed in the table below rather than one being chosen
- what it leaves out
- no grading of infection severity, no separate item for probing to bone or suspected osteomyelitis, no quantified perfusion, and no account of ulcer duration or of previous amputation. The IWGDF publishes a separate infection classification, and the vascular measurements belong to the ankle-brachial pressure index calculator and the toe-brachial index calculator
Worked example
Forefoot (0); reduced pedal flow (1); protective sensation lost (1); no infection (0); ulcer 1 cm² or more (1); confined to skin and subcutaneous tissue (0)
0 + 1 + 1 + 0 + 1 + 0 = 3 points
In the 120-patient cohort read for this page, 21 of 30 patients with a SINBAD of 3 healed — 70 per cent — with no major amputations and 6 disarticulations
That is a description of 30 patients in one series, not a probability for anyone. The score's recommended uses are communication and audit
Add infection and the total becomes 4, where that cohort recorded 17 of 29 healed (58.6 per cent) and 7 major amputations
Make it a midfoot ulcer reaching tendon as well and the total becomes 6, where that cohort recorded 13 major amputations among 22 patients — and where its own healing figure is internally inconsistent
Every item is worth exactly one point, so the score cannot distinguish an ischaemic forefoot ulcer from a large neuropathic one. Both are 1. The six letters have to be communicated alongside the total, which is what the IWGDF means by using the SYSTEM for communication and the SCORE for audit
The six items
| Letter | Item | 0 points | 1 point |
|---|---|---|---|
| S | Site | Forefoot | Midfoot or hindfoot |
| I | Ischaemia | Pedal blood flow intact, at least one palpable pulse | Clinical evidence of reduced pedal blood flow |
| N | Neuropathy | Protective sensation intact | Protective sensation lost |
| B | Bacterial infection | None | Present |
| A | Area | Ulcer under 1 cm² | Ulcer 1 cm² or more |
| D | Depth | Confined to skin and subcutaneous tissue | Reaching muscle, tendon or deeper |
Outcome by SINBAD score in one 120-patient cohort
| Score | Patients | Healed | Healing rate | Major amputations |
|---|---|---|---|---|
| 1 | 9 | 9 | 100% | 0 |
| 2 | 16 | 14 | 87.5% | 0 |
| 3 | 30 | 21 | 70% | 0 |
| 4 | 29 | 17 | 58.6% | 7 |
| 5 | 14 | 1 | 7.1% | 4 |
| 6 | 22 | 2 | 9.1% from the counts, 1.1% in the paper’s own table | 13 |
Six bits of information, and why the simplest system won
There are more than a dozen published classifications for diabetic foot ulcers and the International Working Group on the Diabetic Foot’s 2023 guideline went through them to answer a narrow question: which one should clinicians use to describe an ulcer to each other, and which one should be used for audit. The answer to both was SINBAD, with strong recommendations, and the reason is that it needs nothing but a pair of hands. Six observations, each a yes or no: is the ulcer on the midfoot or hindfoot rather than the forefoot, is pedal flow clinically reduced, is protective sensation lost, is there infection, is it a square centimetre or bigger, and does it reach muscle or tendon or deeper.
The guideline is unusually blunt about the alternatives. Of Wagner’s grades, in use since 1981, it says its group “considered this classification to have a poor clinical discrimination” and that it has “insufficient detail when compared with SINBAD”; Wagner, the University of Texas system and DIAFORA are all listed as not selected for clinical use or audit. The University of Texas system also omits ulcer area entirely and, like WIfI, needs an ankle-brachial index to apply. WIfI keeps a conditional recommendation for communication and a positive one for stratifying healing likelihood and amputation risk where those pressure measurements are available.
The price of that simplicity is that the total carries less information than the six items do. Every item is worth one point, so a score of 2 could be an ischaemic forefoot ulcer or a large deep one, and the two are not the same problem. There is no grading of infection severity — the IWGDF publishes a separate classification for that — no separate item for probing to bone, and no quantified perfusion. That is why the guideline’s wording distinguishes using the SYSTEM for communication from using the SCORE for audit: the letters travel with the number.
Published outcome data by score exist and are printed here with their cohort rather than converted into a probability. A prospective series of 120 patients reported healing falling from 100 per cent at a score of 1 to single figures at 5 and 6, with major amputations appearing only from a score of 4 — and that paper contradicts itself on the score-6 healing rate, so both of its figures appear in the table. One cohort in one centre is a description. If the ankle and toe pressures have been measured, the ankle-brachial pressure index calculator and the toe-brachial index calculator quantify the perfusion this score only asks about, and the toe index exists because a calcified vessel in a neuropathic foot can give a falsely normal ankle index. A score is not a diagnosis, and a number from a derivation cohort is not a probability for the patient in front of you. This page computes the published number and names the guideline or trial that defines its thresholds. It renders no clinical decision.
Frequently asked questions
What does SINBAD stand for?
Site, Ischaemia, Neuropathy, Bacterial infection, Area and Depth. Each is scored 0 or 1, giving a total of 0 to 6. It was published by Ince and colleagues in Diabetes Care in 2008 as a simplification of the earlier S(AD)SAD system.
Which diabetic foot ulcer classification does the IWGDF recommend?
SINBAD, with strong recommendations for two purposes: communication between healthcare professionals about an ulcer’s characteristics, and regional, national or international audit. WIfI has a conditional recommendation for communication and is recommended for stratifying healing likelihood and amputation risk where the ankle and toe pressures are available.
Why not use the Wagner grade?
The IWGDF’s 2023 Classification Guideline states that its group “considered this classification to have a poor clinical discrimination” and that it has “insufficient detail when compared with SINBAD”, and lists Wagner among the systems not selected for clinical use or audit. Wagner is a reproducible 1981 publication; it is simply not the system the international guideline recommends.
Are there published severity bands for the SINBAD total?
Not that this page could find. The IWGDF recommends the score for communication and audit and publishes no mild/moderate/severe banding, so this calculator carries no coloured bands — attaching invented strata to the total would print a stratification nobody published. Per-score outcomes from one 120-patient cohort are given as a table with their cohort.
Does a SINBAD score predict healing for an individual patient?
No. The figures in the table are observed proportions in a single prospective series of 120 patients in one centre, and that paper’s own score-6 healing rate is internally inconsistent. A score from a derivation cohort is not a probability for the patient in front of you, and this page computes none.
Related calculators
References
- International Working Group on the Diabetic Foot. Guidelines on the classification of foot ulcers in people with diabetes, IWGDF 2023 update — the SINBAD table, the recommendations for communication and audit, and the Expert Panel’s assessment of Wagner and the University of Texas system.
- Ince P, et al. Use of the SINBAD classification system and score in comparing outcome of foot ulcer management on three continents. Diabetes Care. 2008;31(5):964–7. The derivation publication.
- Venkataramana AVH, Manjunath BD, Razack A, Harindranath HR, Arish H. A prospective study to determine the application of site, ischemia, neuropathy, bacterial infection and depth scoring in the outcome and management of diabetic foot ulcers. Int Surg J. 2020;7(2):478–83. 120 patients.
Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/