Vascular Calcification in Hemodialysis Patients: A Cross-Sectional, One Center Observational Study
Background and objective: Increasing evidence suggests that vascular calcification is one of the most important factors for outcomes of hemodialysis patients. The use of plain radiography has already been suggested as an adequate replacement for expensive and not easily available methods, such as computed tomography in Kidney Disease: Improving Global Outcomes guidelines for vascular calcification assessment, but it was not widely outspread in everyday clinical practice. Experts highlight the necessity of extended studies using these simple nonexpensive methods. The aim of the study was to evaluate the prevalence and the characteristics of vascular calcification in hemodialysis patients of our center and to identify the impact of vascular calcification on all-cause mortality.
Methods: The observational prospective single-center study included 95 prevalent patients on maintenance hemodialysis in the dialysis unit of the Hospital of Lithuanian University of Health Sciences Kauno klinikos. The simple vascular calcification score (SVCS) was evaluated as it is described by Adragao et al. with SVCS ≥ 3 considered as a cut-off value. For the more detailed analysis, the group of patients with SVCS ≥ 3 was divided into 2 subgroups: SVCS 3–5 (mild vascular calcification) and SVCS 6–8 (severe vascular calcification). The patients were followed from the baseline examination until the death or until the end of May 2017. Demographical, clinical data, and anamnesis of pre-existing diseases were collected from medical records of each patient. Statistical analyses were performed using SPSS 24 software package.
Results: SVCS was evaluated in 95 patients: 54 men (56.8%) and 41 women (43.2%). On the day of SVCS evaluation, the mean age of patients was 61.01 ± 15.7 (22–86) and the mean HD vintage was 39.74 ± 46.2 months (1–182). Nineteen patients (20%) were diabetic, 38 (40%) had diagnosed pre-existing cardiovascular diseases, and most of them 88 (92.6%) were hypertensive. SVCS ≥ 3 was found in 57 patients (60%), and SVCS < 3 in 38 patients (40%). The survival rate
in the group of SVCS < 3 was 92.1%, and it was significantly different compared with the groups of SVCS 3–5 (71.4%) and SVCS 6–8 (44.4%), log-rank 0.001. There was a statistically significant difference in the survival rate comparing groups with SVCS 0–2 and SVCS 3–5 (92.1% vs. 71.4%, respectively, log-rank 0.026). The difference in the groups with SVCS 3–5 vs. SVCS 6–8 did not reach the level of significance (71.4% vs. 44.4 %, respectively, log-rank 0.057). The multivariate logistic regression analysis revealed that age and hemodialysis vintage were important risk factors for mortality, but SVCS ≥ 3 had the highest impact increasing the risk of all-cause mortality by 7.34 times.
Conclusions: Clinical significant vascular calcification was diagnosed in more than a half of patients (60%). The severe injury was present in 22.1% of prevalent patients. Present vascular calcification was associated with the increase in mortality by 7.34 times.
Correspondence to V. Petrauskienė Department of Nephrology, Hospital of Lithuanian University of Health Sciences Kauno klinikos, Eivenių 2A, Kaunas LT-50009, Lithuania E-mail: email@example.com