Transcript The Leeds Dactylitis Index An objective outcome measure

A case control study of predictors of foot ulceration in patients with rheumatoid arthritis
Jill Firth1, Claire Hale1, Philip Helliwell2, Jackie Hill1 and Elizabeth Hensor
1Academic
Unit of Musculoskeletal Nursing, University of Leeds, 2Academic Unit of Musculoskeletal Disease, University of Leeds, 3 , UK
1 Background
4 Results
• Neuropathy, peripheral vascular disease and
foot deformities are known risk factors for the
onset of foot ulceration in diabetes [1].
• Step-wise logistic regression analysis showed that abnormal ABPI was the main predictor of foot ulceration,
followed by current steroid therapy and the presence of pre-ulcerative lesions. Whilst swollen joint count was a
significant predictor of foot ulceration, abnormal sensation, foot deformity and raised plantar pressures were not.
Table 1 gives the coefficients, Wald statistic and odds ratios for each of the predictor values.
• Whilst foot ulcers occur frequently in rheumatoid
arthritis (RA), the factors that influence risk in
this client group are unknown.
2 Objectives
• To test the relationship between identified risk
factors for foot ulceration and foot ulcers
occurring in a sample of RA patients using a
case control approach.
3 Methods
• The cases were 15 RA patients reporting foot
ulceration in response to a postal survey of
patients sampled from a diagnostic register in
secondary care (n=1130).
• The controls were 66 RA patients randomly
sampled from the survey respondents (n=883)
after matching for age, sex and disease
duration.
• Patients with coexistent diabetes were excluded.
• Clinical examination included the following:
sensation (insensitivity to 10g monofilament);
ankle-brachial pressure index (ABPI); foot
deformity (Platto indices) and plantar pressure
(PressureStatTM readings). A 44 joint count, the
presence of pre-ulcerative lesions and current
steroid therapy were identified through
univariate analysis as potential predictors.
• The wide confidence intervals for ABPI were due to sparse data, with very few abnormal values, and the results
of Exact logistic regression (more accurate where numbers are low/ data sparse) found that ABPI was no longer
a significant predictor (p = 0.140). The results did not differ substantially for the other variables.
Variable
B
Wald
Adjusted OR
(95% C.I.)
p value
Steroid
2.272
8.397
9.70 (2.09-45.11)
.004
ABPI
2.599
4.429
13.45 (1.19-151.43)
.035
Pre-ulcerative lesions
2.002
6.086
7.40 (1.51-36.30)
.014
Swollen joint count
Constant
0.222
-3.967
4.508
20.869
1.25 (1.02-1.53)
0.019
.034
0.019
5 Conclusions
6 References
• The aetiology of foot ulceration in RA differs from diabetes. In
this study, abnormal sensation, foot deformity and raised plantar
pressures were not significantly associated with foot ulceration
but active disease and current steroid therapy were.
1. Abbott, C.A., et al., The North-West Diabetes Foot
Care Study: incidence of, and risk factors for,
new diabetic foot ulceration in a communitybased patient cohort. Diabetic Medicine, 2002.
19(5): p. 377-84.
• The contribution of peripheral vascular disease to risk is unclear
and a multi-centre study of incident cases is needed to
investigate this further.
Acknowledgements
Jill Firth is funded by a Smith & Nephew Foundation
Doctoral Scholarship