Table 6 Risk prediction models for Diabetic Foot Ulcer (DFU) development or amputation

Boyko et al. (2006) [15]

Variables:

HbA1C, vision poorer than 20/40, history of foot ulcer, history of amputation, monofilament insensitivity, tinea pedis, onychomycosis

Model:

A1C × 0.0975 + 0.7101 (neuropathy present) + 0.3888 (poor vision)—0.3206 (tinea pedis present) + 0.4579 (onychomycosis present) + 0.7784 (past history of foot ulcer) + 0.943 (past history of lower limb amputation)

Outcome Predicted:

DFU

Time Horizon:

1 and 5 years

Risk Categories:

Quantified by risk score quartiles as below:

Lowest quartile: 0.61–1.47

Second lowest: 1.48–1.99

Second highest: 2.00–2.61

Highest: 2.62–5.07

Martins-Mendes et al. [original] (2014) [17]

Variables:

Physical impairment, PAD complication history, complications count (retinopathy, nephropathy, neuropathy, cerebrovascular, cardiovascular, peripheral arterial disease and metabolic (ketoacidosis, hyperosmolar coma or other coma)), prior DFU

Model:

-3.29 + 0.55 × Physical impairment + 0.93 × PAD complication history presence + 0.27 × number of complications count + 1.51 × Previous DFU

Outcome Predicted:

DFU or amputation

Time Horizon:

3 years

Risk Categories:

unclear

Martins-Mendes et al. [simplified] (2014) [17]

Variables:

Complications count; includes retinopathy, nephropathy, neuropathy, cerebrovascular, cardiovascular, peripheral arterial disease and metabolic (ketoacidosis, hyperosmolar coma or other coma)

Model:

Simplified model for predicting DFU

-2.86 + 0.46 × number of complications^* count + 1.84 × previous DFU

Simplified model for predicting amputation

-5.35 + 0.61 × number of complications count + 1.91 × previous DFU

Outcome Predicted:

DFU or amputation

Time Horizon:

3 years

Risk Categories:

unclear

PODUS 2020 [8]

Variables:

Neuropathy, PAD, history of DFU or lower-extremity amputation

Model:

Quantifies risk with total potential scores 0 to 4 using the sum of:

Score 1 if insensitive to a 10 g monofilament

Score 1 if any pedal pulse is absent (dorsalis pedis and posterior tibial pulses on both feet)

Score 2 if history of previous ulcer or amputation

Outcome Predicted:

DFU

Time Horizon:

2 years

Risk Categories:

Score 0—average risk is 2.4% (95% CI 1.4% to 3.9%) at 2 years

Score 1—average risk is 6.0% (95% CI 3.5% to 9.5%) at 2 years

Score 2—average risk is 14% (95% CI 8.5% to 21%) at 2 years

Score 3—average risk is 29% (95% CI 19% to 41%) at 2 years

Score 4—average risk is 51% (95% CI 38% to 64%) at 2 years