Abdominal aortic calcification is not superior over other vascular calcification in predicting mortality in hemodialysis patients: a retrospective observational study

Background: KDIGO (Kidney Disease: Improving Global Outcomes) guidelines recommend that a lateral abdominal radiograph should be performed to assess vascular calcification (VC) in dialysis patients. However, abdominal aortic calcification is a prevalent finding, and it remains unclear whether other anatomical areas of VC can predict mortality more accurately. Methods: A total of 217 maintenance hemodialysis patients were enrolled at the Sichuan Provincial People's Hospital between July 2010 and March 2011. Radiographs of the abdomen, pelvis and hands were evaluated by a radiologist to evaluate the presence of VC. The correlation between different areas of VC and all-cause or cardiovascular mortality was analyzed using univariate and multivariate models. Results: The prevalence of VC was 70.0% (152 patients), and most had abdominal aortic calcification (90.1%). During 26 +/- 7 months of follow-up, 37 patients died. The VC score was independently associated with patient mortality. VC observed on abdominal radiographs (abdominal aortic calcification) was associated with all-cause mortality in models adjusted for cardiovascular risk factors (HR, 4.69; 95%CI, 1.60-13.69) and dialysis factors (HR, 3.38; 95%CI, 1.18-9.69). VC in the pelvis or hands was associated with all-cause mortality in the model adjusted for dialysis factors. When three combinations of VC in different radiographs were included in models, the presence of abdominal VC was only significantly associated with all-cause mortality in the integrated model. VC in the abdomen and pelvis was associated with all-cause mortality in the model adjusted for cardiovascular factors and the integrated model, but neither was significantly associated with cardiovascular mortality. VC in all radiographs was significantly associated with a more than 6-fold risk of all-cause mortality and a more than 5-fold risk of cardiovascular mortality compared to patients without VC. Conclusions: VC in different arteries as shown on radiographs is associated with different levels of risk for mortality. The lateral abdominal radiograph may not be superior to other radiographs for predicting patient outcomes. Further research is needed to elucidate the effects of difference burdens of VC on patient outcomes.