Vascular Calcification in Chronic Kidney Disease Patients on Hemodialysis: Prevalence and Correlation with Vascular Disease Events

ABSTRACT

Introduction: With declining kidney function, the prevalence of vascular calcifications increases and calcification occurs years earlier and is more severe in chronic kidney disease (CKD) patients than in general population. We did this study to find the prevalence of vascular calcification in patients on maintenance hemodialysis using simple and inexpensive radiological method and to find out the correlation of vascular calcification score with vascular disease events, cardiovascular and all-cause mortality over a follow-up period of 1 year. Materials and methods: This prospective, observational, comparative, follow-up, single-center study of maintenance hemodialysis patients was performed at a tertiary care center in Haryana. Seventy-one patients on maintenance hemodialysis for more than 3 months were included in the study. Patients who were 18 years of age or below, CKD stage 5 patients not on dialysis and those who had previous history of parathyroidectomy were excluded. Adragao score for vascular calcification was calculated by evaluating bilateral iliac, femoral and radial arteries in plain radiographic films of pelvis and hands. Statistical analyses were performed with the SPSS System 10.0. Results: Seventy-one patients were enrolled in this study out of which, 45 were male and 26 were female. Mean age of patients was 61.92 ± 10.77 years. Majority of patients were elderly (age group ?60 years). Out of 71 patients, 66 (92.9%) were hypertensive and 26 (36.6%) patients were diabetic. Twenty-two (30.9%) patients had cardiovascular disease (CVD) at baseline. Coronary artery disease (CAD) was present in 20 (28.1%) patients, cerebrovascular disease was present in 2 (2.8%) patients and peripheral artery disease (PAD) was present in only 1 patient at baseline. Average dialysis duration received by patients was 21.35 ± 21.17 months. Out of 71 patients, 16 (22.5%) received calcium-containing phosphate binder, 51 (71.8%) received noncalcium-containing phosphate binder and 4 patients received no phosphate binder. Fifty-five (77.4%) patients received therapeutic or prophylactic vitamin D3 therapy during the study period. Vascular calcification detected with plain X-ray of pelvis and both wrists was found in 56.3% of patients on maintenance hemodialysis. The prevalence and severity of vascular calcification was higher with increasing age. Diabetes was found to be significantly associated with the presence of vascular calcification (p < 0.0005). CAD at the time of enrollment was significantly associated with vascular calcification (p = 0.009). Serum levels of calcium, phosphate, vitamin D3, intact parathyroid hormone (PTH), calcium-phosphate product or use of phosphate binders or the types or vitamin D therapy did not correlate clinically with presence of vascular calcification. Hemodialysis duration did not correlate with the presence of vascular calcification (p = 0.113). Presence of vascular calcifications in hemodialysis patients predicted future vascular disease events over 1 year follow-up (p = 0.013) but did not correlate with cardiovascular and all-cause mortality. Conclusion: There is a high prevalence of vascular calcification in maintenance hemodialysis patients in our center. The risk factors of vascular calcification were higher age, diabetes and CAD. These patients should be followed-up regularly for vascular events. We also want to reiterate with this study that plain X-ray is sufficient to rule out vascular calcification in CKD patients and should be employed regularly in dialysis clinics.