PEDIS classification: how the five diabetic foot ulcer grades work

PEDIS grades a diabetic foot ulcer on five separate axes: perfusion, extent, depth, infection and sensation. Each gets its own grade, and the result is written as five numbers in that order, such as 1-1-1-1-1. The grades are never added up.

Not a medical device. Not a diagnosis or dosing recommendation.

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What is the PEDIS classification?

PEDIS was developed by the International Working Group on the Diabetic Foot (IWGDF) as a research classification. Schaper described it in a 2004 supplement of the journal Diabetes Metab Res Rev. Its purpose is to describe the ulcers of patients included in research studies in the same way everywhere.

Magent's calculator takes the five grades and returns them with the combined label.

This page explains the grades. It doesn't say what a grade means for a particular person.

The PEDIS grades

P  perfusion   1  no signs or symptoms of peripheral arterial disease (PAD)
               2  PAD without critical limb ischemia
               3  critical limb ischemia
E  extent      1  ulcer area < 1 cm²
               2  1 to 3 cm²
               3  > 3 cm²
D  depth       1  superficial, not through the dermis
               2  into subcutaneous tissue, fascia, muscle or tendon, not bone or joint
               3  bone and/or joint
I  infection   1  none
               2  limited to skin and subcutaneous tissue
               3  deeper than skin, without SIRS
               4  infection with SIRS
S  sensation   1  no loss of protective sensation
               2  loss of protective sensation

label = P-E-D-I-S (not summed)

Exact expression the calculator uses:

PEDIS is five independent Schaper 2004 IWGDF grades, not a summed total: perfusion 1-3 (1 no PAD symptoms/signs; 2 PAD without critical limb ischemia; 3 critical limb ischemia); extent 1-3 (ulcer area 1 <1 cm2; 2 1-3 cm2; 3 >3 cm2); depth 1-3 (1 superficial, not through dermis to subcutaneous; 2 to subcutaneous/fascia/muscle/tendon, not bone/joint; 3 bone and/or joint); infection 1-4 (1 none; 2 skin/subcutaneous only; 3 deeper than skin without SIRS; 4 infection with SIRS); sensation 1-2 (1 no loss of protective sensation; 2 loss of protective sensation). Label is perfusion-extent-depth-infection-sensation

Inputs

Input	Meaning	Grades
`perfusion`	Blood supply to the foot	1 to 3
`extent`	Ulcer area	1 to 3
`depth`	Deepest tissue involved	1 to 3
`infection`	Infection grade	1 to 4
`sensation`	Protective sensation	1 to 2

How the calculation works

Assign each of the five grades from the definitions.
Write them in the order perfusion, extent, depth, infection, sensation, joined by hyphens.

There is no total. A grade of 3 on one axis doesn't trade off against a grade of 1 on another.

Units

Ulcer extent is graded by area in cm². The other axes are graded from findings, not measurements. A grade outside its range is rejected with an error.

Worked examples

These use Magent's own expected values for the calculator.

Example 1: every axis at grade 1

Perfusion 1, extent 1, depth 1, infection 1, sensation 1.
Label 1-1-1-1-1.

Example 2: critical limb ischemia

Perfusion 3; the other axes at grade 1.
Label 3-1-1-1-1.

Example 3: a large ulcer

Extent 3 (over 3 cm²); the other axes at grade 1.
Label 1-3-1-1-1.

Example 4: down to bone or joint

Depth 3; the other axes at grade 1.
Label 1-1-3-1-1.

Example 5: infection with SIRS

Infection 4; the other axes at grade 1.
Label 1-1-1-4-1.

Example 6: loss of protective sensation

Sensation 2; the other axes at grade 1.
Label 1-1-1-1-2.

History of the PEDIS classification

The calculator cites Schaper, Diabetes Metab Res Rev, 2004 (a supplement issue). The abstract notes that many diabetic foot classifications had been proposed without wide acceptance. The IWGDF developed PEDIS for research purposes, with each of the five categories defined by strict criteria meant to apply worldwide, and the system was agreed by consensus of the experts and IWGDF members.

When it's used

PEDIS describes a diabetic foot ulcer in a consistent way, mainly so research studies can report which patients they included.

Where it's used

Grading needs a foot examination: pulses or vascular findings, ulcer size and depth, signs of infection and a sensation test.

Who uses it

The person using the calculator assigns the five grades. The calculator checks each grade's range and returns the label.

Limits of the calculation

The calculator doesn't examine the foot, measure the ulcer, probe to bone or test sensation. Every grade comes from the person entering it.
It returns the research classification. It doesn't return a summed total or extra bands.
It isn't wound care or amputation guidance, and this page doesn't say what to do with a grade.

Clinical decisions belong to a qualified clinician who knows the patient.

LRINEC adds laboratory points for necrotizing soft tissue infection. PEDIS grades an ulcer from examination findings.

Glossary

PAD: peripheral arterial disease, narrowing of the arteries to the legs.
Critical limb ischemia: PAD severe enough to threaten the limb.
SIRS: systemic inflammatory response syndrome, body-wide signs of inflammation.
Protective sensation: enough feeling in the foot to notice injury.

Common mistakes

Adding the grades. PEDIS has no total; the label keeps the five grades apart.
Mixing up the order. The label runs perfusion, extent, depth, infection, sensation.
Giving sensation a grade of 3. Sensation has two grades.
Grading infection limited to skin and subcutaneous tissue as 3. That is grade 2.

Source

Schaper NC. Diabetic foot ulcer classification system for research purposes: a progress report on criteria for including patients in research studies. Diabetes Metab Res Rev. 2004;20 Suppl 1:S90-S95. DOI: 10.1002/dmrr.464. PMID: 15150820

Frequently asked questions

What does PEDIS stand for?

Perfusion, extent, depth, infection and sensation.

Why isn't there a PEDIS total?

The five grades describe different things, so they are kept separate in the label.

What does a PEDIS label like 1-1-3-1-1 mean?

Every axis is at grade 1 except depth, which is grade 3: bone and/or joint.

What is infection grade 2?

Infection limited to skin and subcutaneous tissue.

Who developed PEDIS?

The International Working Group on the Diabetic Foot, for research use.