Serum leptin levels are positively associated with aortic stiffness in patients with chronic kidney disease stage 3–5

Figures & data

Table 1. Clinical variables of the 205 chronic kidney disease patients with or without aortic stiffness

Characteristics	All Patients (n = 205)	Control Group (n = 132)	Aortic Stiffness Group (n = 73)	P value
Age (years)	69.07 ± 13.43	66.08 ± 14.09	74.48 ± 10.20	< 0.001*
Height (cm)	158.78 ± 8.79	158.90 ± 8.72	158.57 ± 8.99	0.794
Body weight (kg)	66.35 ± 14.31	65.95 ± 14.53	67.08 ± 13.99	0.592
Body mass index (kg/m^2)	26.18 ± 4.45	25.99 ± 4.62	26.52 ± 4.14	0.413
Waist circumference (cm)	87.24 ± 10.95	85.83 ± 11.07	89.81 ± 10.32	0.012*
Body fat mass (%)	28.83 ± 8.39	27.86 ± 8.81	30.58 ± 7.32	0.025*
cfPWV (m/s)	9.00 (7.25–11.20)	7.80 (6.63–8.98)	12.40 (10.90–14.70)	< 0.001*
SBP (mmHg)	149.40 ± 24.44	145.14 ± 23.67	157.12 ± 24.07	0.001*
DBP (mmHg)	83.59 ± 12.82	83.04 ± 12.61	84.58 ± 13.22	0.412
Total cholesterol (mmol/l)	4.20 ± 1.11	4.20 ± 1.19	4.21 ± 0.96	0.957
Triglyceride (mmol/l)	1.40 (1.02–1.89)	1.35 (1.00–1.85)	1.46 (1.07–1.95)	0.333
LDL-C (mmol/l)	2.38 ± 0.94	2.38 ± 1.00	2.39 ± 0.82	0.918
Fasting glucose (mmol/l)	5.44 (5.16–6.94)	5.38 (5.11–6.74)	5.83 (5.24–7.49)	0.049*
Blood urea nitrogen (mmol/l)	11.78 (8.21–17.14)	10.89 (8.21–18.12)	13.57 (9.82–16.60)	0.213
Creatinine (µmol/l)	176.80 (128.18–247.52)	172.38 (123.76–247.52)	185.64 (137.02–243.10)	0.296
eGFR (mL/min)	30.98 ± 15.18	32.43 ± 16.13	28.36 ± 13.00	0.066
Total calcium (mmol/l)	2.20 (2.15–2.31)	2.20 (2.13–2.30)	2.22 (2.17–2.32)	0.200
Phosphorus (mmol/l)	1.23 ± 0.26	1.24 ± 0.27	1.20 ± 0.25	0.289
Leptin (ng/ml)	8.79 (5.02–15.90)	7.76 (3.90–13.15)	11.60 (6.26–27.52)	< 0.001*
Female, n (%)	92 (44.9)	62 (47.0)	30 (41.1)	0.418
Diabetes mellitus, n (%)	95 (46.3)	52 (39.4)	43 (58.9)	0.007*
Hypertension, n (%)	170 (82.9)	111 (84.1)	59 (80.8)	0.551
Glomerulonephritis, n (%)	54 (26.3)	39 (29.5)	15 (20.5)	0.161
CCB, n (%)	89(43.4)	52(39.4)	37(50.4)	0.118
ACEi, n (%)	8(3.9)	6(4.5)	2(2.7)	0.523
ARB, n (%)	105(51.2)	67(50.8)	38(52.1)	0.118
Beta blocker, n (%)	61(29.8)	38(28.8)	23(31.5)	0.683
Statin, n (%)	90(43.9)	56(42.4)	34(46.6)	0.566
Fibrate, n (%)	19(9.3)	13(9.8)	6(8.2)	0.700
CKD stage 3, n (%)	99 (48.3)	69 (52.3)	30 (30.3)	0.153
CKD stage 4, n (%)	67 (32.7)	37 (28.0)	30 (41.1)
CKD stage 5, n (%)	39 (19.0)	26 (19.7)	13 (17.8)

Values for continuous variables are given as mean ± standard deviation and tested by Student’s t-test; variables not normally distributed are given as median and interquartile range and tested by Mann–Whitney U test; values are presented as number (%) and analysis was done using the chi-square test.

cfPWV, carotid–femoral pulse wave velocity; SBP, systolic blood pressure; DBP, diastolic blood pressure; LDL-C, low-density lipoprotein cholesterol; eGFR, estimated glomerular filtration rate; ARB, angiotensin-receptor blocker; ACE, angiotensin-converting enzyme; CCB, calcium-channel blocker; CKD, chronic kidney disease.

*P < 0.05 was considered statistically significant.

Table 2. Multivariate logistic regression analysis of the factors correlated to aortic arterial stiffness among 205 chronic kidney disease patients

Variables	Odds ratio	95% confidence interval	P value
Leptin, ng/ml	1.061	1.027–1.095	< 0.001*
Age, year	1.064	1.033–1.096	< 0.001*
Systolic blood pressure, mmHg	1.021	1.006–1.037	0.006*
Diabetes mellitus, present	2.111	0.968–4.602	0.060
Body fat mass, %	1.035	0.992–1.079	0.110
Waist circumference, cm	1.013	0.979–1.048	0.449
Fasting glucose, mmol/l	1.012	0.863–1.186	0.886

Analysis data was done using the multivariate logistic regression analysis (adopted factors: diabetes mellitus, age, waist circumference, body fat mass, systolic blood pressure, fasting glucose, and leptin).

*P < 0.05 was considered statistically significant.

Adjusted R² = 0.350. Overall model P value < 0.001.

Table 3. Correlation between carotid-femoral pulse wave velocity levels and clinical variables among the 205 chronic kidney disease patients

	Log-cfPWV (m/s)
	Univariate			Multivariate
Variables	r	P value		Beta	Adjusted R^2 change	P value
Female	−0.123	0.080		–	–	–
Diabetes mellitus	0.203	0.003*		0.157	0.021	0.008*
Hypertension	0.058	0.411		–	–	–
Glomerulonephritis	−0.107	0.127		–	–	–
Age (years)	0.353	< 0.001*		0.308	0.098	< 0.001*
Height (cm)	0.035	0.618		–	–	–
Body weight (kg)	0.106	0.130		–	–	–
Body mass index (kg/m^2)	0.105	0.135		–	–	–
Waist circumference (cm)	0.249	< 0.001*		–	–	–
Body fat mass (%)	0.081	0.249		–	–	–
SBP (mmHg)	0.392	< 0.001*		0.352	0.150	< 0.001*
DBP (mmHg)	0.156	0.026*		–	–	–
TCH (mmol/l)	−0.041	0.560		–	–	–
Log-Triglyceride (mmol/l)	0.084	0.233		–	–	–
LDL-C (mmol/l)	−0.085	0.223		–	–	–
Log-Glucose (mmol/l)	0.112	0.111		–	–	–
Log-BUN (mmol/l)	0.086	0.222		–	–	–
Log-Creatinine (µmol/l)	0.106	0.129		–	–	–
eGFR (ml/min)	−0.184	0.008*		–	–	–
Log-Calcium (mmol/l)	0.069	0.322		–	–	–
Phosphorus (mmol/l)	−0.052	0.459		–	–	–
Log-Leptin (ng/ml)	0.237	0.001*		0.192	0.042	0.001*

Data of carotid–femoral pulse wave velocity, triglyceride, glucose, BUN, creatinine, calcium, and leptin levels showed skewed distribution and therefore were log-transformed before analysis.

Analysis of data was done using the univariate linear regression analyses or multivariate stepwise linear regression analysis (adapted factors were diabetes mellitus, age, waist circumference, SBP, DBP, eGFR, and log-leptin).

cfPWV, carotid–femoral pulse wave velocity; SBP, systolic blood pressure; DBP, diastolic blood pressure; TCH, total cholesterol; LDL-C, low-density lipoprotein cholesterol; BUN, blood urea nitrogen; eGFR, estimated glomerular filtration rate.

*P < 0.05 was considered statistically significant.