Absolute iron deficiency, coronary artery calcification and cardiovascular mortality in maintenance haemodialysis patients.

AIM: The effects of iron on vascular calcification in rats and vascular smooth muscle cells were recently reported, but clinical studies on iron and vascular calcification are scant. We studied the associations of absolute iron deficiency, coronary artery calcification and mortality in patients with maintenance haemodialysis (MHD). METHODS: Transferrin saturation (TSAT), ferritin, mean corpuscular haemoglobin (MCH) and Agatston coronary artery calcium score (CACS) were studied at baseline in MHD patients and followed up for 3 years. Cox proportional hazard analyses for mortality and linear regression analyses for CACS were performed. RESULTS: In 306 patients, the median age was 67 (56-81) years, dialysis duration was 76 (38-142) months, and diabetes prevalence was 42.5%. Fifty-two patients had died by 3 years. Patients with absolute iron deficiency (TSAT <20% and ferritin <100 ng/mL) (n = 102) showed significantly higher CACS (p = .0266) and C-reactive protein (p = .0011), but a lower frequency of iron formulation administration compared with patients without absolute iron deficiency at baseline (n = 204). Absolute iron deficiency was a significant predictor for 3-year cardiovascular (CV) mortality (hazard ratio: 2.08; p = .0466), but not for 3-year all-cause mortality. CACS was significant predictor for both 3-year CV and all-cause mortality (p <.05). Absolute iron deficiency and MCH were significant determinants of CACS (p < .05). CONCLUSION: MHD patients with absolute iron deficiency showed significantly higher CACS than others, and absolute iron deficiency was a significant risk factor for coronary artery calcification and 3-year CV mortality in MHD patients, but was not a significant predictor for 3-year all-cause mortality.

Effects of overhydration, Kt/Vurea, ß2-microglobulin on coronary artery calcification and mortality in haemodialysis patients.

AIM: We studied the effects of overhydration (OH), Kt/Vurea and ß2-microglobulin (ß2-MG) on coronary artery calcification and mortality in patients undergoing haemodialysis (HD). METHODS: The Agatston coronary artery calcium score (CACS), postdialysis body composition using bioimpedance analysis, single-pool Kt/Vurea and predialysis ß2-MG at baseline were assessed and followed up for 3 years in patients undergoing HD. We performed logistic regression analyses for a CACS ≥400 and Cox proportional hazard analyses for all-cause and cardiovascular mortality. RESULTS: The study involved 338 patients with a median age of 67 (56-74) years, dialysis duration of 70 (33-141) months and diabetes prevalence of 39.1% (132/338). Patients with a CACS ≥400 (n = 222) had significantly higher age, dialysis duration, male prevalence, diabetes prevalence, C-reactive protein, predialysis ß2-MG, OH, extracellular water/total body water and overhydration/extracellular water (OH/ECW) but significantly lower Kt/Vurea than patients with a CACS <400 (n = 116) (p < .05). OH/ECW, Kt/Vurea and predialysis ß2-MG were significant predictors of a CACS ≥400 (p < .05) after adjusting for age, dialysis duration, serum phosphate and magnesium. In all patients, cut-off values of OH/ECW, Kt/Vurea and predialysis ß2-MG for a CACS ≥400 were 16%, 1.74 and 28 mg/L, respectively. After adjusting for dialysis duration, OH/ECW ≥16%, Kt/Vurea ≥1.74 and ß2-MG ≥28 mg/L were significant predictors of 3-year all-cause mortality but not 3-year cardiovascular mortality. CONCLUSION: Higher OH/ECW, higher predialysis ß2-MG and lower Kt/Vurea values are significant risk factors for a CACS ≥400 and 3-year all-cause mortality in patients undergoing maintenance HD.