Abdominal aortic calcification score can predict all-cause and cardiovascular mortality in maintenance hemodialysis patients

Figures & data

Figure 1. Receiver operating characteristic (ROC) analysis of the baseline abdominal aortic calcification (AAC) score for mortality. The area under the ROC curve is 0.714 (95% confidence interval, 0.659–0.769, p < 0.001). The cutoff value of the AAC score is 4.5 (sensitivity 67.3%, specificity 70.4%).

Figure 2. Kaplan–Meier analysis of all-cause and cardiovascular deaths of 408 hemodialysis patients. The blue line denotes the patients with an AAC score ≤ 4.5 (248 patients) and the green line denotes the patients with an AAC score > 4.5 (160 patients). (a) The patients with an AAC score > 4.5 had a higher death rate from all causes than those with an AAC score ≤ 4.5 (log-rank test, p < 0.001). (b) The patients with an AAC score > 4.5 had a higher death rate from cardiovascular mortality than those with an AAC score ≤ 4.5 (log-rank test, p < 0.001).

Table 1. Demographic characteristics of hemodialysis patients with AAC scores below and above 4.5.

	Group A AAC score ≤ 4.5 (248)	Group B AAC score >4.5 (160)	p Value
Age, (years)	50.7 ± 12.9	62.0 ± 10.2	<0.001
Duration of HD, (years)	7 (5)	8.5 (6)	<0.001
Men, n (%)	159 (64.1%)	91 (36.4%)	0.143
Smoking, n (%)	53 (21.4%)	36 (22.5%)	0.787
Hypertension history, n (%)	196 (79%)	129 (80.6%)	0.696
Diabetes, n (%)	48 (19.4%)	50 (31.3%)	0.006
Cardiovascular disease, n (%)	22 (8.9%)	38 (23.8%)	<0.001
calcium-based phosphate binders, n (%)	120 (48.4%)	70 (43.8%)	0.359
calcium-free phosphate binders, n (%)	148 (59.7%)	103 (64.4%)	0.341
vitamin D medications, n (%)	189 (78.2%)	122 (73.1%)	0.237
Cinacalcet, n (%)	50 (20.2%)	24 (15%)	0.187
ACEi or ARB	118 (47.6%)	91 (56.9%)	0.067
Causes of kidney disease			0.142
nephritis, n (%)	124 (50%)	69 (43.1%)
diabetes, n (%)	52 (21%)	28 (17.5%)
hypertension, n (%)	43 (17.3%)	42 (26.3%)
others	29 (11.7%)	21 (13.1%)
Daily average blood pressure	106.3 ± 17.4	103.2 ± 17.4	0.076
Kt/V	1.2 ± 0.3	1.3 ± 0.3	0.395
CVD death, (%)	23 (9.3%)	56 (35%)	<0.001
All cause death, (%)	34 (13.7%)	70 (43.8%)	<0.001
CVC, n (%)	57 (23%)	102 (63.7%)	<0.001
AAC score	1.1 ± 1.4	9.6 ± 3.7	<0.001
BMI (kg/m2)	22.9 ± 3.8	22.5 ± 3.0	0.199
LAD (cm)	3.4 ± 0.5	3.6 ± 0.6	0.047
LVDd (cm)	4.8 ± 0.6	4.8 ± 0.6	0.972
IVST (cm)	1.2 ± 0.2	1.2 ± 0.1	0.158
Lvpwt (cm)	1.2 ± 0.1	1.2 ± 0.1	0.083
LVMI (g/m2)	120.8 (48.7)	128.1 (41.9)	0.049
EF	0.63 (0.07)	0.62 (0.07)	0.501
E/A	1 (0.6)	0.8 (0.4)	0.009
HGB (g/L)	113.0 ± 15.1	110.0 ± 15.8	0.056
Ca (mmol/L)	2.2 ± 0.2	2.3 ± 0.2	0.032
P (mmol/L)	2.0 ± 0.6	1.9 ± 0.6	0.192
β2-microglobulin (mg/L)	26.8 ± 6.5	29.4 ± 6.5	<0.001
iPTH (pg/ml)	296.5 (420)	200 (440)	0.004
ALB (g/L)	39.1 ± 3.5	38.0 ± 3.8	0.004
UA (μmol/L)	463.3 ± 109.3	434.8 ± 89.5	0.006
25-OH-VD (ng/ml)	15.2 ± 8.2	14.4 ± 7.3	0.414
TG (mmol/L)	1.5 (1.2)	1.4 (1.0)	0.751
TC (mmol/L)	4.2 ± 1.1	4.3 ± 1.0	0.576
HDL-C (mmol/L)	1.2 ± 0.3	1.2 ± 0.3	0.678
LDL-C (mmol/L)	2.2 ± 0.7	2.3 ± 0.7	0.130

CVC: cardiac valve calcification; AAC: abdominal aortic calcific; BMI: body mass index; LAD: left atrial dimension; LVDd: left ventricular end-diastolic internal dimension; IVST: interventricular septal wall thickness; Lvpwt: left ventricular posterior wall thickness; LVMI: left ventricular mass index; EF: ejection fraction; E/A: the ratio of the E wave and A wave; iPTH: intact parathyroid hormone; ALB: albumin; UA: uric acid; 25-OH-VD: 25 hydroxy vitamin D; TG: triglyceride; TC: total cholesterol; Ca: Serum total Calcium; P: Serum Phosphate.

The variables conforming to a normal distribution are presented as the mean and SD.

The variables (duration of HD, E/A, EF, LVMI, TG, iPTH and 25-OH-VD) conforming to a nonnormal distribution are presented as the median and IQR.

Table 2. Univariate Cox proportional hazards analysis of factors associated with all-cause and cardiovascular death in hemodialysis patients.

	All-cause mortality		Cardiovascular mortality
Variable	HR (95%)	p Value	HR (95%)	p Value
CVC (Ref: no)	3.242 (2.169–4.845)	<0.001	4.079 (2.524–6.592)	<0.001
AAC score >4.5 (Ref: no)	3.908 (2.593–5.891)	<0.001	4.584 (2.819–7.454)	<0.001
Age (per each 1 year increase)	1.052 (1.036–1.068)	<0.001	1.052 (1.034–1.071)	<0.001
Duration of HD (per each 1 year increase)	0.983 (0.936–1.031)	0.477	0.968 (0.914–1.026)	0.271
Sex (male vs. female)	0.994 (0.670–1.476)	0.977	1.07 (0.677–1.690)	0.772
Smoking (Ref: no)	1.193 (0.761–1.871)	0.441	1.274 (0.767–2.116)	0.349
Hypertension history (Ref: no)	0.899 (0.565–1.428)	0.651	1.293 (0.713–2.343)	0.397
Diabetes (Ref: no)	2.276 (1.533–3.380)	<0.001	2.465 (1.572–3.865)	<0.001
Cardiovascular disease (Ref: no)	2.330 (1.494–3.634)	<0.001	2.838 (1.746–4.614)	<0.001
calcium-based phosphate binders (Ref: no)	1.141 (0.777–1.675)	0.503	0.862 (0.552–1.345)	0.512
calcium-free phosphate binders (Ref: no)	0.711 (0.483–1.045)	0.082	0.897 (0.572–1.406)	0.635
vitamin D medications (Ref: no)	0.579 (0.384–0.873)	0.009	0.609 (0.379–0.979)	0.041
Cinacalcet (Ref: no)	0.438 (0.228–0.84)	0.013	0.465 (0.224–0.965)	0.04
ACEi or ARB (Ref: no)	1.085 (0.738–1.594)	0.678	1.095 (0.704–1.703)	0.688
Daily average blood pressure (per 1 mmHg)	0.998 (0.987–1.009)	0.682	1.007 (0.994–1.021)	0.301
Kt/V (per 1 increase)	1.838 (0.957–3.531)	0.068	1.475 (0.681–3.194)	0.324
BMI (per 1 kg/m2 increase)	0.977 (0.922–1.035)	0.425	0.982 (0.92–1.049)	0.594
LAD (per 1 cm increase)	1.795 (1.302–2.474)	<0.001	2.074 (1.456–2.955)	<0.001
LVH (Ref: no)	1.421 (0.906–2.228)	0.126	1.767 (1.021–3.058)	0.042
EF	0.056 (0.007–0.465)	0.008	0.026 (0.003–0.266)	0.002
E/A	1.041 (0.638–1.699)	0.087	1.212 (0.71–2.07)	0.481
HGB (per 1 g/L increase)	0.983 (0.971–0.996)	0.008	0.997 (0.963–0.991)	0.002
β2-microglobulin (per 1 mg/L increase)	1.047 (1.017–1.078)	0.002	1.056 (1.021–1.093)	0.001
TG (per 1 mmol/L increase)	0.571 (0.435–0.749)	<0.001	0.573 (0.42–0.782)	<0.001
TC (per 1 mmol/L increase)	0.844 (0.694–1.026)	0.089	0.872 (0.698–1.089)	0.226
HDL-C (per 1 mmol/L increase)	1.398 (0.77–2.538)	0.271	0.914 (0.439–1.904)	0.810
LDL-C (per 1 mmol/L increase)	0.847 (0.633–1.135)	0.266	0.963 (0.696–1.332	0.821
ALB (per 1 g/L increase)	0.884 (0.844–0.926)	<0.001	0.879 (0.834–0.927)	<0.001
UA (per 1 μmol/L increase)	0.997 (0.996–0.999)	0.007	0.997 (0.995–0.999)	0.007
25-OH-VD (per 1 ng/ml increase)	0.979 (0.952–1.007)	0.133	0.979 (0.948–1.011)	0.191
iPTH 150–300 pg/mL (as reference)
iPTH < 150 pg/mL	1.076 (0.665–1.741)	0.767	1.013 (0.587–1.747)	0.963
iPTH > 300 pg/mL	0.67 (0.414–1.084)	0.103	0.611 (0.352–1.058)	0.79
Ca 2.1–2.5 mmol/L (as reference)
Ca < 2.1 mmol/L	1.178 (0.746–1.86)	0.483	1.008 (0.598–1.725)	0.977
Ca > 2.5 mmol/L	1.642 (0.935–2.884)	0.084	1.348 (0.684–2.655)	0.388
P 1.13–1.78 mmol/L (as reference)
p < 1.13 mmol/L	0.998 (0.48–2.076)	0.995	1.583 (0.729–3.438)	0.246
p > 1.78 mmol/L	0.859 (0.566–1.303)	0.474	1.093 (0.660–1.810)	0.730

CVC: cardiac valve calcification; AAC: abdominal aortic calcific; BMI: body mass index; LAD: left atrial dimension; LVH: left ventricular hypertrophy; EF: ejection fraction; E/A: the ratio of the E wave and A wave; TG: triglyceride; TC: total cholesterol; ALB: albumin; UA: uric acid; 25-OH-VD: 25 hydroxy vitamin D; iPTH: intact parathyroid hormone; Ca: Serum total Calcium; P: Serum Phosphate.

Table 3. Multivariate Cox proportional hazards analysis of factors associated with all-cause and cardiovascular death in hemodialysis patients.

	All-cause mortality		Cardiovascular mortality
Variable	HR (95%)	p Value	HR (95%)	p Value
AAC score > 4.5 (Ref: no)	2.079 (1.299–3.326)	0.002	2.610 (1.523–4.472)	<0.001
CVC (Ref: no)	1.783 (1.135–2.801)	0.012	2.219 (1.297–3.796)	0.004
Age (per each 1 year increase)	1.022 (1.003–1.041)	0.021	–	–
Diabetes (Ref: no)	2.043 (1.353–3.083)	0.001	2.269 (1.423–3.618)	0.001
LAD (per 1 cm increase)	1.419 (1.027–1.961)	0.034	1.656 (1.027–1.961)	0.005
Alb (per 1 g/L increase)	0.931 (0.882–0.983)	0.009	0.916 (0.864–0.972)	0.004
TG (per 1 mmol/L increase)	0.560 (0.415–0.755)	<0.001	0.570 (0.405–0.802)	0.001

AAC: abdominal aortic calcific; CVC: cardiac valve calcification; LAD: left atrial dimension; TG: triglyceride.

Data availability statement

Datasets are available from the corresponding author on reasonable request.