Serum fatty acid binding protein 4 levels are associated with abdominal aortic calcification in peritoneal dialysis patients

Figures & data

Table 1. Comparison of clinical characteristics in accordance with serum FABP4 level.

Characteristics	All patients (n = 116)	FABP4 < 150.1ng/mL (n = 58)	FABP4 ≥ 150.1ng/mL (n = 58)	p value
Age (years)	57.0 ± 13.7	56.7 ± 15.5	57.2 ± 11.8	0.845
Male (n)	56 (48.3%)	31 (53.4%)	25 (43.1%)	0.265
Diabetic mellitus (n)	37 (31.9%)	26 (44.8%)	11 (19.0%)	0.003
History of cardiovascular disease (n)	47 (40.5%)	20 (34.5%)	27 (46.6%)	0.186
PD vintage (months)	50.0 (17.0, 87.0)	34.0 (7.0, 65.0)	63.5 (32.0, 93.0)	0.003
BMI (kg/m^2)	23.4 ± 3.7	22.8 ± 4.0	24.1 ± 3.3	0.064
Systolic BP (mmHg)	133.6 ± 16.1	137.2 ± 13.2	129.9 ± 17.9	0.014
Diastolic BP (mmHg)	79.5 ± 12.3	80.3 ± 12.3	78.7 ± 12.2	0.465
Dialysate glucose load (g/d)	99.9 (88.6, 109.8)	97.2 (81.0, 109.8)	103.2 (97.2, 113.0)	0.088
Total Kt/V urea (per week)	1.83 (1.57, 2.16)	2.03 (1.72, 2.30)	1.72 (1.50, 1.87)	0.002
Residual kidney Kt/V urea (per week)	0.96 (0.00, 0.55)	0.31 (0.00, 0.76)	0.00 (0.00, 0.21)	0.002
Hemoglobin (g/L)	116.4 ± 16.2	116.7 ± 16.0	116.0 ± 16.5	0.824
Serum us-CRP (mg/L)	3.32 (0.89, 9.29)	1.73 (0.63, 7.01)	4.44 (2.08, 12.92)	0.003
Albumin (g/L)	37.4 ± 3.9	37.1 ± 3.6	37.8 ± 4.2	0.312
Creatinine (μmol/L)	931.5 ± 253.0	878.0 ± 261.5	985.0 ± 234.4	0.022
Corrected calcium (mmol/L)	2.53 ± 0.23	2.52 ± 0.21	2.54 ± 0.25	0.717
Phosphate (mmol/L)	1.63 ± 0.41	1.56 ± 0.39	1.70 ± 0.42	0.072
Ca × P (mg^2/dL^2)	51.0 ± 13.0	48.6 ± 11.5	53.4 ± 14.1	0.048
iPTH (pg/mL)	158.6 (85.1, 325.9)	142.4 (74.3, 232.1)	219.2 (99.1, 416.4)	0.007
ALP (U/L)	69.0 (57.0, 86.0)	63.5 (55.5, 74.5)	77.0 (59.8, 104.8)	0.003
Fasting blood glucose (mmol/L)	5.6 (4.8, 6.7)	5.7 (4.9, 9.0)	5.5 (4.8, 6.1)	0.209
HbA1c (%)	6.1 (5.5, 7.0)	6.4 (5.5, 7.4)	5.9 (5.2, 6.3)	0.185
TCHO (mmol/L)	4.78 ± 1.10	4.64 ± 0.98	4.91 ± 1.21	0.176
TG (mmol/L)	1.80 (1.34, 2.97)	1.57 (1.12, 2.64)	2.29 (1.48, 3.35)	0.003
HDL-C (mmol/L)	0.97 (0.83, 1.13)	0.98 (0.86, 1.16)	0.97 (0.79, 1.11)	0.229
LDL-C (mmol/L)	2.78 ± 0.77	2.74 ± 0.68	2.81 ± 0.85	0.609
Body composition (n = 110)
Lean body mass (kg)	38.0 ± 9.9	39.2 ± 9.5	36.7 ± 10.2	0.187
Skeletal muscle mass (kg)	35.2 ± 9.1	36.2 ± 8.6	34.3 ± 9.5	0.277
Body fat mass (kg)	24.6 ± 11.0	22.1 ± 11.3	26.8 ± 10.2	0.024
Body fat percentage (%)	38.5 ± 14.3	34.8 ± 13.7	42.0 ± 14.0	0.007
Overhydration value (OH, L)	1.8 (0.8, 2.8)	2.1 (1.0, 2.9)	1.5 (0.7, 2.6)	0.067
Statin use, n	57 (49.1%)	31 (53.4%)	26 (44.8%)	0.353
Calcium carbonate use, n	71 (61.2%)	34 (53.5%)	37 (63.8%)	0.568
Non-calcium-containing phosphate binder use, n	41 (35.3%)	20 (34.5%)	21 (36.2%)	0.846
Calcitriol use, n	19 (16.4)	8 (13.8%)	11 (19.0%)	0.452
Serum FABP4 (ng/mL)	150.1 (131.6, 223.3)	131.6 (112.9, 140.2)	222.3 (169.6, 388.9)	＜0.001
AAC score	4.0 (1.0, 10.0)	3.0 (1.0, 6.0)	9.0 (2.0, 13.0)	<0.001
AAC score ≥4 (n)	61 (52.6%)	24 (41.4%)	37 (63.8%)	0.016

FABP4: fatty acid binding protein 4; PD: peritoneal dialysis; BMI: body mass index; BP: blood pressure; Kt/V urea: fractional urea clearance; us-CRP: ultra-sensitive C reactive protein; iPTH: intact parathyroid hormone; ALP: alkaline phosphatase; HbA1c: glycosylated hemoglobin; TCHO: total cholesterol; TG: triglyceride; HDL-C: high density lipoprotein cholesterol; LDL-C: low density lipoprotein cholesterol; AAC: abdominal aortic calcification.

Table 2. Comparison of clinical characteristics among PD patients with an AAC score <4 or ≥4.

Characteristics	AAC score <4 (n = 55)	AAC score ≥4 (n = 61)	p value
Age (years)	51.7 ± 13.0	61.7 ± 12.7	<0.001
Male (n)	26 (47.3%)	30 (49.2%)	0.837
Diabetic mellitus (n)	12 (21.8%)	25 (41.0%)	0.027
History of cardiovascular disease	13 (23.6%)	34 (55.7%)	<0.001
PD vintage (months)	43.0 (12.0, 91.0)	51.0 (27.0, 83.5)	0.488
Dialysate glucose load (g/d)	97.2 (81.0, 109.8)	109.8 (97.2, 109.8)	0.088
Total Kt/V urea (per week)	1.83 (1.67, 2.16)	1.82 (1.54, 2.17)	0.616
Residual kidney Kt/V urea (per week)	0.19 (0.00, 0.69)	0.00 (0.00, 0.45)	0.236
Systolic BP (mmHg)	135.5 ± 15.1	131.8 ± 16.8	0.214
Diastolic BP (mmHg)	84.3 ± 10.0	75.1 ± 12.5	<0.001
us-CRP (mg/L)	1.56 (0.63, 4.87)	7.15 (2.30, 15.25)	<0.001
Albumin (g/L)	38.6 ± 3.4	36.3 ± 4.0	0.001
Fasting blood glucose (mmol/L)	5.3 (4.7, 5.9)	5.7 (5.1, 7.2)	0.097
HbA1c (%)	6.0 (5.1, 7.1)	6.1 (5.6, 6.9)	0.660
Corrected calcium (mmol/L)	2.49 ± 0.22	2.57 ± 0.23	0.045
Corrected calcium > 2.54 mmol/L (n)	19 (34.5%)	36 (59.0%)	0.008
Phosphate (mmol/L)	1.63 ± 0.46	1.62 ± 0.37	0.909
Phosphate >1.45 mmol/L (n)	30 (54.5%)	45 (73.8%)	0.031
Ca × P (mg^2/dL^2)	50.1 ± 13.4	51.9 ± 12.8	0.464
iPTH (pg/mL)	157.4 (70.1, 333.5)	159.8 (101.0, 316.8)	0.569
ALP (U/L)	67.0 (55.0, 79.0)	73.0 (59.5, 107.0)	0.054
TCHO (mmol/L)	4.72 ± 0.91	4.82 ± 1.26	0.610
TG (mmol/L)	1.62 (1.35, 2.62)	2.36 (1.33, 3.24)	0.148
HDL-C (mmol/L)	0.98 (0.86, 1.17)	0.95 (0.80, 1.11)	0.102
LDL-C (mmol/L)	2.80 ± 0.76	2.75 ± 0.78	0.704
Body composition (n = 110)
Lean body mass (kg)	39.3 ± 10.0	36.9 ± 9.8	0.208
Skeletal muscle mass (kg)	37.1 ± 9.6	33.7 ± 8.4	0.052
Body fat mass (kg)	22.3 ± 10.8	26.4 ± 10.9	0.048
Body fat percentage (%)	35.4 ± 14.7	41.1 ± 13.5	0.035
Overhydration value (OH, L)	1.9 (0.9, 2.9)	1.8 (0.8, 2.8)	0.851
Statin use, n	16 (29.1%)	41 (67.2%)	<0.001
Calcium carbonate use, n	35 (63.6%)	36 (59.0%)	0.523
Non-calcium-containing phosphate binder use, n	20 (36.4%)	21 (34.4%)	0.827
Calcitriol use, n	8 (14.5%)	11 (18.0%)	0.612
AAC score	1.0 (0.0, 2.0)	9.0 (7.0, 13.0)	<0.001
Serum FABP4 (ng/mL)	144.7 (123.8, 170.1)	164.5 (138.4, 362.8)	0.002

PD: peritoneal dialysis; AAC: abdominal aortic calcification; Kt/V: fractional urea clearance; BP: blood pressure; us-CRP: ultra-sensitive C reactive protein; HbA1c: glycosylated hemoglobin; iPTH: intact parathyroid hormone; ALP: alkaline phosphatase; TCHO: total cholesterol; TG: triglyceride; HDL-C: high density lipoprotein cholesterol; LDL-C: low density lipoprotein cholesterol; FABP4: fatty acid binding protein 4.

Figure 1. Correlations between serum FABP4, AAC score, and other clinical parameters.

Table 3. Correlations between the AAC score, serum FABP4 level, and other parameters.

Variables	AAC score		Serum FABP4 (ng/mL)
	r	p value	r	p value
Age (years)	0.423	<0.001	0.033	0.728
PD vintage (months)	0.110	0.240	0.304	0.001
Systolic BP (mmHg)	−0.120	0.200	−0.205	0.027
Diastolic BP (mmHg)	−0.375	<0.001	−0.133	0.157
Total Kt/V urea (per week)	−0.174	0.107	−0.343	0.001
Residual kidney Kt/V urea (per week)	−0.293	0.006	−0.375	<0.001
BMI (kg/m^2)	0.164	0.080	0.229	0.014
Fasting blood glucose (mmol/L)	0.151	0.107	−0.063	0.500
HbA1c (%)	0.042	0.750	−0.094	0.471
Hemoglobin (g/L)	0.018	0.845	0.018	0.850
Albumin (g/L)	−0.259	0.005	0.086	0.356
Creatinine (μmol/L)	−0.042	0.653	0.270	0.003
Corrected calcium (mmol/L)	0.189	0.042	0.035	0.708
Phosphate (mmol/L)	0.019	0.841	0.233	0.012
Ca × P (mg^2/dL^2)	0.079	0.398	0.227	0.014
TG (mmol/L)	0.237	0.010	0.286	0.002
HDL-C (mmol/L)	−0.206	0.027	−0.155	0.096
LDL-C (mmol/L)	−0.023	0.809	−0.002	0.985
TCHO (mmol/L)	0.059	0.528	0.156	0.095
ALP (U/L)	0.224	0.016	0.239	0.010
iPTH (pg/mL)	0.060	0.522	0.236	0.011
us-CRP (mg/L)	0.405	<0.001	0.315	0.001
Serum FABP4 (ng/mL)	0.416	<0.001	–	–
Skeletal muscle mass (kg)	−0.265	0.005	−0.171	0.075
Body fat mass (kg)	0.266	0.005	0.286	0.002
Body fat percentage (%)	0.293	0.002	0.312	0.001
Lean body mass (kg)	−0.223	0.019	−0.193	0.043
Overhydration value (OH, L)	−0.002	0.981	−0.250	0.011

AAC: abdominal aortic calcification; FABP4: fatty acid binding protein 4; PD: peritoneal dialysis; BP: blood pressure; Kt/V urea: fractional urea clearance; BMI: body mass index; HbA1c: glycosylated hemoglobin; TG: triglyceride; HDL-C: high density lipoprotein cholesterol; LDL-C: low density lipoprotein cholesterol; TCHO: total cholesterol; ALP: alkaline phosphatase; iPTH: intact parathyroid hormone; us-CRP: ultra-sensitive C reactive protein.

Table 4. Univariate and multivariate linear regression analysis for the AAC score.

Parameters	Univariate linear regression		Multivariate linear regression
	β	p value	β	p value
Age (years)	0.135	<0.001	0.100	0.007
History of cardiovascular disease (%)	2.990	0.002	Not selected	–
Systolic BP (mmHg)	−0.059	0.047	Not selected	–
Diastolic BP (mmHg)	−0.158	<0.001	Not selected	–
Residual kidney Kt/V urea (peer week)	−3.501	0.011	Not selected	–
Albumin (g/L)	−0.282	0.021	−0.291	0.020
Corrected calcium (mmol/L)	4.220	0.042	Not selected	–
TG (mmol/L)	0.714	0.001	Not selected	–
HDL-C (mmol/L)	−4.235	0.016	Not selected	–
us-CRP (mg/L)	0.134	0.002	Not selected	–
Serum FABP4 (ng/mL)	0.024	<0.001	0.026	<0.001
Skeletal muscle mass (kg)	−0.159	0.003	Not selected	–
Body fat mass (kg)	0.140	0.001	Not selected	–

AAC: abdominal aortic calcification; BP: blood pressure; Kt/V urea: fractional urea clearance; TG: triglyceride; HDL-C: high density lipoprotein cholesterol; us-CRP: ultra-sensitive C reactive protein; FABP4: fatty acid binding protein 4.

Table 5. Independent factors associated with an AAC score ≥4 by logistic regression analysis.

Parameters	Univariate		Multivariate
	Exp (B) (95% CI)	p value	Exp (B) (95% CI)	p value
Age (years)	1.062 (1.029–1.096)	<0.001	1.134 (1.065–1.206)	<0.001
Diabetic mellitus	2.488 (1.098–5.641)	0.029	34.578 (5.885–203.161)	<0.001
History of cardiovascular disease (%)	4.068 (1.826–9.067)	0.001	Not selected	–
Diastolic BP (mmHg)	0.928 (0.892–0.965)	<0.001	Not selected	–
Albumin (g/L)	0.841 (0.754–0.940)	0.002	0.788 (0.636–0.976)	0.029
Corrected calcium >2.54 mmol/L	2.728 (1.283–5.802)	0.009	3.982 (1.150–13.782)	0.029
Phosphate >1.45 mmol/L	2.344 (1.075–5.109)	0.032	10.766 (2.699–42.939)	0.001
ALP (U/L)	1.016 (1.001–1.031)	0.037	Not selected	–
TG (mmol/L)	1.237 (1.005–1.523)	0.037	Not selected	–
HDL-C (mmol/L)	0.231 (0.051–1.052)	0.058	Not selected	–
us-CRP (mg/L)	1.092 (1.030–1.158)	0.003	Not selected	–
Serum FABP4 (ng/mL)	1.006 (1.002–1.010)	0.003	1.015 (1.007–1.023)	<0.001
Skeletal muscle mass (kg)	0.958 (0.918–1.001)	0.055	Not selected	–
Body fat mass (kg)	1.036 (1.000–1.074)	0.051	Not selected	–

AAC: abdominal aortic calcification; BP: blood pressure; ALP: alkaline phosphatase; TG: triglyceride; HDL-C: high density lipoprotein cholesterol; us-CRP: ultra-sensitive C reactive protein; FABP4: fatty acid binding protein 4.

Data availability statement

The data underlying this article will be shared upon reasonable request to the corresponding author.