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

Abstract

BackgroundAdults with end-stage renal disease treated with dialysis experience a high burden of foot ulceration and lower extremity amputation. However, the risk factors for foot ulceration in the dialysis population are incompletely understood due to the lack of high-quality prospective evidence. This article outlines the design of a prospective observational cohort study, which aims to investigate the risk factors for foot ulceration in adults on dialysis.Methods/DesignThis study will recruit 430 participants with end-stage renal disease on dialysis from satellite and home-therapy dialysis units across multiple health organisations in Melbourne, Victoria, Australia. Data collection at baseline will include a participant interview, medical record review, completion of a health-status questionnaire and a non-invasive foot assessment. Twenty participants will also be recruited to a reliability study to evaluate the reproducibility of testing procedures. Primary outcome data includes: new foot ulcer(s). Secondary outcome data includes: number of new foot ulcers, time to onset of new foot ulcer(s), new lower extremity amputation(s), episodes of infection of the foot or lower extremity, episodes of osteomyelitis, foot-related hospitalisations, revascularisation procedure(s) of the lower extremity, new podiatry interventions, kidney transplantation, and mortality. Participants will be assessed at baseline, and at 12 months they will be evaluated for the primary and secondary outcomes. Multivariate Cox proportional hazards models will be used to assess predictors of new foot ulceration and time to event secondary outcomes. Logistic regression will be used for binary outcomes including prevalence of foot ulcerations.DiscussionThis is the first multi-centre prospective observational cohort study to investigate risk factors for foot ulceration in adults with end-stage renal disease on dialysis. This study will improve on prior studies by using prospective methods, multi-centre recruitment, statistical methods to control for confounding variables, and a pre-specified sample size estimation. The findings can inform the design of future trials evaluating the effectiveness of clinical interventions, which may lead to improved patient outcomes in the dialysis setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s13047-015-0110-9) contains supplementary material, which is available to authorized users.

Factors associated with foot ulceration and amputation in adults on dialysis: a cross-sectional observational study

“…Data investigated in this study are baseline data from a prospective cohort study – detailed inclusion criteria, recruitment and methods are published elsewhere [ 14 ]. Here we describe participant characteristics at baseline and conduct a cross-sectional analysis of the prevalence of lower limb complications and factors associated with foot ulceration and amputation.…”

“…collected the data and performed all foot assessments. Details of the participant interview, medical record review, and other methods, including validity and reliability, have been previously described [ 14 ].…”

“…Skin and nail pathologies were assessed visually, as previously described [ 14 ]. Inappropriate footwear was defined as poor shoe fit, inappropriate shoe style and/or poor shoe condition [ 21 ].…”

“…Inappropriate footwear was defined as poor shoe fit, inappropriate shoe style and/or poor shoe condition [ 21 ]. Foot-health care behaviors were self-reported according to a series of five questions [ 14 ]. Foot-health care behavior was considered ‘poor’ if participants answered ‘no’ to three or more questions.…”

“…To ensure reliability of the foot assessments, 20 participants were assessed on two separate occasions spaced 1 week apart by the same blinded examiner (M.R.K.). Details for intra-examiner reliability have been described elsewhere [ 14 ], and results are shown in Additional file 1 . Briefly, intra-class correlation coefficients ranged from 0.87 to 0.99 for continuous data and all weighted kappa values equaled 1.00 with the absolute percentage of agreement ranging from 95 to 100% for dichotomous data.…”