Mayfield et al developed a risk score for predicting lower extremity amputation secondary to diabetes mellitus in Pima Indians. This can help identify patients who may benefit from more aggressive management and closer monitoring. The authors are from Indiana University, Veterans Affairs Puget Sound Health Care System, the National Institute of Diabetes and Digestive and Kidney Disease, and the Cleveland Clinic.
Patient selection:
(1) age 25 to 85 years of age
(2) 50% or more Pima or Tohono O'odham Indian
(3) lived in the Gila River Indian Community during a 10 year period (1983-1992)
Parameters for the risk classification system:
(1) peripheral neuropathy
(2) peripheral vascular disease
(3) bony deformity
(4) foot ulcer
|
Parameter
|
Finding
|
Points
|
|
peripheral neuropathy
|
absent
|
0
|
|
|
present
|
1
|
|
peripheral vascular disease
|
absent
|
0
|
|
|
present
|
1
|
|
bony deformity
|
absent
|
0
|
|
|
present
|
1
|
|
foot ulcer
|
none
|
0
|
|
|
duration <= 4 weeks
|
0
|
|
|
duration > 4 weeks
|
1
|
sum of risk factors =
= SUM(points for all 4 risk factors)
Interpretation:
• minimum number of risk factors: 0
• maximum number of risk factors: 4
• The risk of amputation increases with the number of risk factors
|
Number of Risk Factors
|
Odds Ratio for Amputation
|
Risk Level
|
|
0
|
1.0
|
low
|
|
1
|
2.1
|
low to moderate
|
|
2
|
4.5
|
moderate
|
|
3 or 4
|
9.7
|
high
|
after Table 7, page 708
A patient with one or more of the risk factors should be:
(1) have greater surveillance
(2) receive patient education on risk reduction
(3) referral to a foot care specialist
Additional risk factors for amputation (logistic regression model in Table 6, page 708):
(1) male gender
(2) older age
(3) longer duration of diabetes mellitus
(4) poorer diabetes control (as measured by blood glucose level)
(5) severe diabetic complications (nephropathy, retinopathy, cardiovascular disease)
