**3.2 Diabetic patients on renal dialysis**

Another group of diabetic patients in which the kidney contributes to DFU development or progression are those receiving dialysis therapy. Dialysis patients who have markedly higher risks of DFU or amputation include those with previous foot ulceration or amputation, diabetes mellitus, DPN, or macrovascular disease [115, 116]. Other studies also found that reduced mobility and dexterity due to dialysis may impair the patient's ability to perform foot inspection or foot self-care. In addition, prolonged periods of inactivity on a dialysis couch for at least three times in a week could further contribute or worsen DFU by enhancing the development of pressure ulcers (prolonged pressure-induced skin injury) [117]. A retrospective study of 90 diabetic patients on dialysis therapy showed a high incidence of DFU and amputation before the start of dialysis, with a further increase following 2 years after dialysis initiation [115]. Therefore, it can be inferred that the dialysis treatment was a driving force in DFU progression and its complications. Such a negative effect of dialysis on DFU was later supported by the findings from a multiethnic study in which 400 diabetic patients on dialysis were reported to be at high risk for foot complications [118]. This finding was confirmed in another study by the same authors in which dialysis independently increased the risk for DFU in 137 diabetic patients, with an odd ration of 4.2 after including diabetic neuropathy, peripheral vascular disease, foot self-care measures and other potential confounders [119]. Miyajima et al. [102] also observed that major amputation rates are markedly increased in diabetic patients undergoing hemodialysis, with dismal prognosis while only half of diabetic patients on dialysis avoided major amputation regardless of revascularization [103]. In another study, amputation rate was reported to be 57% among diabetic patients receiving hemodialysis while 25% was reported in their counterparts with pre-dialysis ESRD [96]. In the same vein, diabetic patients on dialysis with critical foot ischemia had 8.9 times increased risk of poor prognosis [120].

McGrath and associate [121] also studied a close relationship between the time of dialysis initiation and development of diabetic foot complications. In a majority of diabetic patients, they found that the period from commencement of dialysis to amputation was less than 1 year, with the median being 7 months. Their observation was later corroborated by the findings of Game et al. [115] who reported a significant increase in the rate DFU onset by 3.3 (95% CI, 1.59–7.04) in the first year after commencement of dialysis while that between the second and fifth years increased by 4.56 (95% CI, 2.19–9.50). In the same study, the authors further reported that the increases in the incidence of major amputation were 31.98 (95% CI, 2.09–490.3) and 34.01 (95% CI, 1.74–666.2) in the first year and second to fifty year of dialysis
