Risk factors of the progression of abdominal aortic calcification in patients on chronic haemodialysis

Background. Vascular calcification is an independent determinantof cardiovascular events in maintenance haemodialysis (HD) patients.It is not known whether acute changes of the serum calcium concentrationbefore and after HD (Ca) are associated with the developmentof aortic calcification. Methods. We enrolled 71 patients dialysed with a dialysate with3.0 mEq/l calcium and determined their aortic calcificationindex (ACI) by abdominal computed tomography twice at an intervalof 3 years. To identify the factors contributing to the rateof progression of aortic calcification, we analysed the averagevalues for clinical and laboratory data obtained between thefirst and second evaluations of ACI. Results. The second ACI (mean ± SD: 80.2 ± 63.9)was significantly greater than the first ACI (61.0 ±61.0) after an interval of 35.8 ± 4.2 months. The annualizedchange of ACI (ACI/year) was significantly and directly associatedwith the Ca and C-reactive protein (CRP) (both P < 0.001,P for trend). Stepwise multivariate regression analysis revealedthat ACI/year was positively and independently associated withCRP, presence of diabetes mellitus and Ca, but negatively associatedwith a premenopausal status in women. Similarly, Ca was positivelyand independently associated with ACI/year and the ultrafiltrationrate, but was negatively associated with pre-HD Ca. Conclusion. The increase of serum calcium after HD was relatedto the rate of progression of aortic calcification. Excess calciumis transferred into patients on HD when using a dialysate of3.0 mEq/l calcium. This may be a risk factor for the developmentof vascular calcification.