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Table 9 Risk factors and potential confounding variables

From: Risk factors for foot ulceration in adults with end-stage renal disease on dialysis: study protocol for a prospective observational cohort study

Continuous variables Categorical variables
Participant characteristics Participant characteristics
 • Age  • Male sex
 • Body mass index  • Current smoker
Health-related quality of life (SF-36v2®)  • Living alone
 • Physical Component Score Comorbidities
 • Mental Component Score  • Diabetes mellitus
Comorbidities  • Retinopathy
 • Duration of diabetes  • Peripheral neuropathy
Dialysis-related variables  • Peripheral arterial disease
 • Duration of dialysis  • Arterial calcification
Laboratory blood tests  • Hypertension
 • C-reactive protein  • Dyslipidaemia
 • Serum albumin  • Ischaemic heart disease
 • Total calcium  • Congestive cardiac failure
 • Serum phosphate  • Cerebrovascular disease
 • Parathyroid hormone  • Osteoarthritis
 • Glycated haemoglobin (HbA1c)  • Inflammatory arthritis
 • Haemoglobin Lower extremity complications
Other  • Previous foot ulceration
 • Peak plantar pressures  • Current foot ulcer present at baseline
 • Previous lower extremity amputation
 • Reduced range of motion of the 1st metatarsophalangeal joint
 • Foot deformity
 • Inappropriate/ill-fitting footwear
 • Skin pathology
 • Nail pathology
 • Poor foot health care behaviours
 • Regular podiatry attendance
  1. Potential confounding variables that will be considered in the regression models are boldface