Progression of aortic calcification is associated with disorders of mineral metabolism and mortality in chronic dialysis patients.

BACKGROUND

Previous studies have shown that simple imaging methods may be useful for detection of vascular calcifications in dialysis patients. Based on annual, plain chest X-rays during follow-up on dialysis, we studied the associations of mineral metabolism with the presence and progression of aortic calcification. In addition, we assessed the impact of aortic calcification on mortality.

METHODS

Three hundred and eighty-four patients who started haemodialysis or peritoneal dialysis between 1997 and 2007 were included (age 61 ± 15 years, 64% male, 61% haemodialysis). Annual chest X-rays were screened for calcification in the aortic arch, and patients were categorized as having no, moderate or severe calcification. Progression was defined as an increase in calcification category during follow-up on dialysis.

RESULTS

At baseline, 96 (25%) patients had severe, 205 (53%) patients had moderate and 83 (22%) patients had no aortic calcification. For 237 of the 288 patients with no or moderate calcifications at baseline, X-rays were available for follow-up. During follow-up (mean 2.3 years), aortic calcification progressed in 71 patients (30%). We found that baseline plasma calcium > 9.5 mg/dL and iPTH > 300 pg/mL were associated with progression [odds ratios of 3.1, 95% confidence interval (1.2-8.2) and 4.4 (1.4-14.1), respectively]. Progression of aortic calcification was significantly associated with increased risk of all-cause mortality (hazard ratio: 1.9; 95% CI: 1.2-3.1) and cardiovascular mortality (hazard ratio: 2.7; 95% CI: 1.3-5.6).

CONCLUSIONS

Aortic calcification progressed in almost a third of the patients during dialysis. Hypercalcaemia and hyperparathyroidism were associated with an increased risk of progression. Progression of aortic calcification was significantly related to an increased mortality risk.