The predictors of foot ulceration in patients with rheumatoid arthritis

This study was conducted to determine the predictorsof foot ulceration occurring in patients with rheumatoidarthritis (RA) without diabetes. A multi-centre case controlstudy was undertaken; participants were recruited from eightsites (UK). Cases were adults diagnosed with RA (withoutdiabetes) and the presence of a validated foot ulcer, defined asa full thickness skin defect occurring in isolation on / belowthe midline of the malleoli and requiring > 14 days to heal.Controls met the same criteria but were ulcer naive. Clinicalexamination included loss of sensation (10g monofilament, ankle-brachial pressure index (ABPI); forefoot deformity(Platto); plantar pressures (PressureStat); RA disease activity(36 swollen/tender joint counts) and the presence of vasculitis.History taking included past ulceration/foot surgery; currentmedication and smoking status. Participants completed theHealth Assessment Questionnaire (HAQ) and Foot Impact Scale.A total of 83 cases with 112 current ulcers and 190 ulcer naïvecontrols participated. Cases were significantly older (mean age71 years; 95 % confidence interval [CI], 69–73 vs. 62 years, 60–64) and had longer RA disease duration (mean 22 years; 19–25vs. 15, 13–17). Univariate analysis showed that risk of ulcerationincreases with loss of sensation; abnormality of ABPI and footdeformity. Plantar pressures and joint counts were not significantpredictors. HAQ score and history of foot surgery were stronglyassociated with ulceration (odds ratio [OR]=1.704, 95 % CI1.274–2.280 andOR=2.256, 95%CI 1.294–3.932). Three casesand two controls presented with suspected cutaneous vasculitis.In logistic regression modelling, ABPI (OR=0.04; 95 % CI,0.01–0.28) forefoot deformity (OR=1.14; 95 % CI, 1.08–1.21)and loss of sensation (OR=1.22; 95 % CI, 1.10–1.36) predictedrisk of ulceration. In patients with RA, ABPI, forefoot deformityand loss of sensation predict risk of ulceration but, in contrastwith diabetes, raised plantar pressures do not predict risk.