Vascular calcification score on plain radiographs of the feet as a predictor of peripheral arterial disease in patients with chronic kidney disease

Background The incidence of lower extremity amputation is increasing in patients with chronic kidney disease (CKD), but symptoms of peripheral arterial disease (PAD) in patients with CKD are uncommon. The aim of the current study was to assess the value of the vascular calcification (VC) score on plain radiographs of the feet for the prediction of PAD in patients with CKD. Methods We recruited 102 patients with CKD (24 pre-dialysis, 58 hemodialysis [HD], and 20 peritoneal dialysis [PD]). We defined the VC score on the plain radiographs of the feet as follows: score 0, no calcification; score 1, the length of the VC is <5 cm in a single foot or <2 cm in both feet; and score 2, the length of the VC is >5 cm in a single foot or >2 cm in both feet. We evaluated the atherosclerotic calcified plaques of the femoral or popliteal artery with Doppler ultrasonography and compared it with the VC score. Results Patients with high VC scores showed more atherosclerotic calcified plaques in the femoral or popliteal artery (P < 0.01). The prevalence of PAD in patients with CKD was closely related with the VC score (P < 0.01). PAD was associated with diabetes, a higher hsCRP, and a lower total cholesterol level (P < 0.01). The VC score was a significant predictor of the presence of PAD (odds ratio: 6.66, P < 0.001). Conclusions Asymptomatic CKD patients, including those on HD and PD, may have PAD and routine testing by plain radiographs of the feet followed by Doppler ultrasonography are of pivotal significance, especially if the patients are diabetic.