Atrial fibrillation and low vitamin D levels are associated with severe vascular calcifications in hemodialysis patients

Background/aims: Vascular calcifications (VCs) and fractures are major complications of chronic kidney disease. Hemodialysis patients have a high prevalence of atrial fibrillation (AF) and an increased risk of thromboembolism, which should be prevented with warfarin, a drug potentially causing increased risk of VCs and fractures. Aim of this study is evaluating, in hemodialysis patients with and without AF, the prevalence of VCs and fractures, as well as identifying the associated risk factors.

Methods: A total of 314 hemodialysis patients were recruited, 101 with documented AF and 213 without AF. Comorbidities, chronic kidney disease mineral and bone disorder blood tests and therapies were collected. Vertebral quantitative morphometry was carried out centrally for the detection of fractures, defined as vertebral body reduction by ≥20 %. In the same radiograph, the length of aortic calcification was also measured. Logistic regression models were applied for evaluating the independent predictors of presence of VCs and vertebral fractures.

Results: In our population VCs were very common (>85 %). Severe VCs (>10 cm) were more common in patients with AF (76 %) than in patients without (33 %). Vertebral fractures were present in 54 % of patients. Multivariable analysis showed that AF (OR 5.41, 95 % CI 2.30-12.73) and 25(OH) vitamin D <20 ng/mL (OR 2.05, 95 % CI 1.10-3.83) were independent predictors of VCs. Age (OR 1.04/year, 95 % CI 1.01-1.07) and male gender (OR 1.76, 95 % CI 1.07-2.90) predicted vertebral fractures.

Conclusions: Hemodialysis patients had an elevated prevalence of severe VCs, especially when affected by AF. Low vitamin D levels were strongly associated with severe VCs. Prevalence of vertebral fractures was also remarkably high and associated with older age and male gender.