J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Original Article

Volume 10, Number 3, March 2018, pages 260-267

The Role of C-Peptide as Marker of Cardiometabolic Risk in Women With Polycystic Ovary Syndrome: A Controlled Study

**Table 1.** Clinical, Metabolic and Hormonal Baseline Characteristics of Normal Cycling Women and Polycystic Ovary Syndrome Patients
Variables	Control	PCOS	P*
PCOS: polycystic ovary syndrome. *Pearson’s correlation coefficient.
Clinical
SBP (mm Hg)	114.07	0.59	117.90	0.61	< 0.001
DBP (mm Hg)	73.25	0.55	75.56	0.54	0.002
Anthropometrical
Body weight (kg)	63.57	0.75	74.76	0.87	< 0.001
BMI (kg/m²)	24.51	0.30	29.00	0.33	< 0.001
WC (cm)	73.51	0.59	85.79	0.75	< 0.001
W/H ratio	0.74	0.00	0.79	0.00	< 0.001
CI	1.07	0.00	1.15	0.00	< 0.001
FM (kg)	19.85	0.51	28.69	0.62	< 0.001
LBM (kg)	43.49	0.34	36.68	0.41	< 0.001
VAI	0.76	0.03	2.43	0.11	< 0.001
Metabolic
Glucose (nmol/L)	4.67	0.03	5.00	0.03	< 0.001
Insulin (µmol/L)	50.91	2.34	97.92	3.36	< 0.001
HbA1C (%)	4.99	0.03	5.80	0.15	< 0.001
C-peptide (nmol/L)	0.54	0.01	0.77	0.02	< 0.001
C-pep/glucose ratio	0.11	0.00	0.015	0.00	< 0.001
Insulin/C-pep ratio	104.88	4.83	130.87	3.45	< 0.001
C-pep/insulin ratio	0.02	0.01	0.002	0.001	<0.001
LAP	15.73	0.99	47.02	2.62	< 0.001
HOMA-IR	0.98	0.04	1.82	0.06	< 0.001
HOMA %B	103.39	3.17	137.96	2.95	< 0.001
HOMA S	138.13	5.86	80.54	2.86	< 0.001
TC (mmol/L)	4.33	0.54	4.69	0.50	0.624
TG (mmol/L)	0.93	0.02	1.60	0.13	< 0.001
HDL (< 0.001 mmol/L)	1.46	0.06	1.18	0.01	< 0.001
LDL-c (mmol/L)	2.58	0.09	2.91	0.07	0.004
VLDL-c (mmol/L)	0.45	0.01	0.62	0.02	< 0.001
Hormonal
Testo T (nmol/L)	1.05	0.03	1.95	0.04	< 0.001
Free T (pmol/L)	0.01	0.00	0.04	0.00	< 0.001
FAI (%)	2.17	0.12	6.93	0.27	< 0.001
FEI (%, pg/nmol)	0.53	0.01	0.66	0.02	< 0.001
E2 (pmol/L)	177.92	6.60	242.75	10.15	< 0.001
17-OHP4 (nmol/L)	2.59	0.08	3.65	0.11	< 0.001
PRL (pmol/L)	695.91	25.56	571.66	15.51	< 0.001

Table 1. Clinical, Metabolic and Hormonal Baseline Characteristics of Normal Cycling Women and Polycystic Ovary Syndrome Patients

Variables

Control

PCOS

Mean

SEM

Mean

SEM

PCOS: polycystic ovary syndrome. *Pearson’s correlation coefficient.

Clinical

SBP (mm Hg)

114.07

0.59

117.90

0.61

< 0.001

DBP (mm Hg)

73.25

0.55

75.56

0.54

0.002

Anthropometrical

Body weight (kg)

63.57

0.75

74.76

0.87

< 0.001

BMI (kg/m²)

24.51

0.30

29.00

0.33

< 0.001

WC (cm)

73.51

0.59

85.79

0.75

< 0.001

W/H ratio

0.74

0.00

0.79

0.00

< 0.001

1.07

0.00

1.15

0.00

< 0.001

FM (kg)

19.85

0.51

28.69

0.62

< 0.001

LBM (kg)

43.49

0.34

36.68

0.41

< 0.001

VAI

0.76

0.03

2.43

0.11

< 0.001

Metabolic

Glucose (nmol/L)

4.67

0.03

5.00

0.03

< 0.001

Insulin (µmol/L)

50.91

2.34

97.92

3.36

< 0.001

HbA1C (%)

4.99

0.03

5.80

0.15

< 0.001

C-peptide (nmol/L)

0.54

0.01

0.77

0.02

< 0.001

C-pep/glucose ratio

0.11

0.00

0.015

0.00

< 0.001

Insulin/C-pep ratio

104.88

4.83

130.87

3.45

< 0.001

C-pep/insulin ratio

0.02

0.01

0.002

0.001

<0.001

LAP

15.73

0.99

47.02

2.62

< 0.001

HOMA-IR

0.98

0.04

1.82

0.06

< 0.001

HOMA %B

103.39

3.17

137.96

2.95

< 0.001

HOMA S

138.13

5.86

80.54

2.86

< 0.001

TC (mmol/L)

4.33

0.54

4.69

0.50

0.624

TG (mmol/L)

0.93

0.02

1.60

0.13

< 0.001

HDL (< 0.001 mmol/L)

1.46

0.06

1.18

0.01

< 0.001

LDL-c (mmol/L)

2.58

0.09

2.91

0.07

0.004

VLDL-c (mmol/L)

0.45

0.01

0.62

0.02

< 0.001

Hormonal

Testo T (nmol/L)

1.05

0.03

1.95

0.04

< 0.001

Free T (pmol/L)

0.01

0.00

0.04

0.00

< 0.001

FAI (%)

2.17

0.12

6.93

0.27

< 0.001

FEI (%, pg/nmol)

0.53

0.01

0.66

0.02

< 0.001

E2 (pmol/L)

177.92

6.60

242.75

10.15

< 0.001

17-OHP4 (nmol/L)

2.59

0.08

3.65

0.11

< 0.001

PRL (pmol/L)

695.91

25.56

571.66

15.51

< 0.001

**Table 2.** Simple Correlation Between C-Peptide and Selected Clinical, Anthropometrical, Hormonal and Metabolic Cardiovascular Risk Markers in Polycystic Ovary Syndrome and Normal Cycling Women
Variables	PCOS	Control
PCOS: polycystic ovary syndrome. *Pearson’s correlation coefficient.
Clinical
SBP (mm Hg)	0.314	0.000	0.016	0.808
DBP (mm Hg)	0.265	0.000	0.072	0.285
Anthropometrical
Body weight (kg)	0.509	0.000	0.356	0.000
BMI (kg/m²)	0.581	0.000	0.332	0.000
WC (cm)	0.565	0.000	0.428	0.000
W/H ratio	0.459	0.000	0.258	0.000
CI	0.353	0.000	0.240	0.000
FM (kg)	0.549	0.000	0.376	0.000
LBM (kg)	0.311	0.000	0.267	0.000
VAI	0.539	0.000	0.317	0.000
Metabolic
Glucose (nmol/L)	0.381	0.000	0.294	0.000
Insulin (µmol/L)	0.602	0.000	0.621	0.000
HbA1C (%)	0.351	0.000	0.187	0.007
C-peptide (nmol/L)	-	-	-	-
C-pep/glucose ratio	0.967	0.000	0.974	0.000
Insulin/C-pep ratio	-0.164	0.002	-0.231	0.002
C-pep/insulin ratio	0.167	0.001	0.234	0.002
LAP	0.434	0.000	0.433	0.000
HOMA-IR	0.592	0.000	0.630	0.000
HOMA %B	0.445	0.000	0.387	0.000
HOMA S	-0.543	0.000	-0.517	0.000
TC (mmol/L)	0.218	0.000	0.041	0.537
TG (mmol/L)	0.452	0.000	0.271	0.000
HDL (mmol/L)	-0.349	0.000	-0.097	0.144
LDL-c (mmol/L)	0.119	0.027	-0.007	0.920
VLDL-c (mmol/L)	0.418	0.000	0.404	0.000
Hormonal
Testo T (nmol/L)	0.182	0.000	0.018	0.782
Free F (pmol/L)	0.322	0.000	0.146	0.027
FAI (%)	0.457	0.000	0.250	0.000
E2 (pmol/L)	0.146	0.009	0.076	0.275
FEI (%, pg/nmol)	0.517	0.00	0.421	0.000
17-OHP4 (nmol/L)	-0.036	0.486	-0.079	0.238
PRL (pmol/L)	-0.191	0.000	0.115	0.087

Table 2. Simple Correlation Between C-Peptide and Selected Clinical, Anthropometrical, Hormonal and Metabolic Cardiovascular Risk Markers in Polycystic Ovary Syndrome and Normal Cycling Women

Variables

PCOS

Control

PCOS: polycystic ovary syndrome. *Pearson’s correlation coefficient.

Clinical

SBP (mm Hg)

0.314

0.000

0.016

0.808

DBP (mm Hg)

0.265

0.000

0.072

0.285

Anthropometrical

Body weight (kg)

0.509

0.000

0.356

0.000

BMI (kg/m²)

0.581

0.000

0.332

0.000

WC (cm)

0.565

0.000

0.428

0.000

W/H ratio

0.459

0.000

0.258

0.000

0.353

0.000

0.240

0.000

FM (kg)

0.549

0.000

0.376

0.000

LBM (kg)

0.311

0.000

0.267

0.000

VAI

0.539

0.000

0.317

0.000

Metabolic

Glucose (nmol/L)

0.381

0.000

0.294

0.000

Insulin (µmol/L)

0.602

0.000

0.621

0.000

HbA1C (%)

0.351

0.000

0.187

0.007

C-peptide (nmol/L)

C-pep/glucose ratio

0.967

0.000

0.974

0.000

Insulin/C-pep ratio

-0.164

0.002

-0.231

0.002

C-pep/insulin ratio

0.167

0.001

0.234

0.002

LAP

0.434

0.000

0.433

0.000

HOMA-IR

0.592

0.000

0.630

0.000

HOMA %B

0.445

0.000

0.387

0.000

HOMA S

-0.543

0.000

-0.517

0.000

TC (mmol/L)

0.218

0.000

0.041

0.537

TG (mmol/L)

0.452

0.000

0.271

0.000

HDL (mmol/L)

-0.349

0.000

-0.097

0.144

LDL-c (mmol/L)

0.119

0.027

-0.007

0.920

VLDL-c (mmol/L)

0.418

0.000

0.404

0.000

Hormonal

Testo T (nmol/L)

0.182

0.000

0.018

0.782

Free F (pmol/L)

0.322

0.000

0.146

0.027

FAI (%)

0.457

0.000

0.250

0.000

E2 (pmol/L)

0.146

0.009

0.076

0.275

FEI (%, pg/nmol)

0.517

0.00

0.421

0.000

17-OHP4 (nmol/L)

-0.036

0.486

-0.079

0.238

PRL (pmol/L)

-0.191

0.000

0.115

0.087

**Table 3.** Stepwise Multiple Correlation Between C-Peptide and Known Predictors of Dysmetabolic Disease in Normal Cycling Women
Model	R	R²	Adjusted R²	Standard error of estimate	Change statistics	Sig. F change	Durbin- Watson
aPredictor: (constant), fasting C-peptide/glucose ratio. ^bPredictor: (constant), fasting C-peptide/glucose ratio, glucose. ^cPredictor: (constant), fasting C-peptide/glucose ratio, glucose, VAI.
1	0.962a	0.926	0.925	0.058021	0.935	962.028	0.000
2	0.996^b	0.993	0.993	0.017985	0.068	5,368.995	0.000
3	0.997^c	0.994	0.993	0.173384	0.000	3,833.105	0.000	1.979

Table 3. Stepwise Multiple Correlation Between C-Peptide and Known Predictors of Dysmetabolic Disease in Normal Cycling Women

Model

R²

Adjusted R²

Standard error of estimate

Change statistics

Sig. F change

Durbin- Watson

R² change

F change

aPredictor: (constant), fasting C-peptide/glucose ratio. ^bPredictor: (constant), fasting C-peptide/glucose ratio, glucose. ^cPredictor: (constant), fasting C-peptide/glucose ratio, glucose, VAI.

0.962a

0.926

0.925

0.058021

0.935

962.028

0.000

0.996^b

0.993

0.017985

0.068

5,368.995

0.000

0.997^c

0.994

0.993

0.173384

0.000

3,833.105

0.000

1.979

**Table 4.** Stepwise Multiple Regression Between C-Peptide and Known Predictors of Dysmetabolic Disease in Patients With Polycystic Ovary Syndrome
Model	R	R²	Adjusted R²	Standard error of estimate	Change statistics	Sig. F change	Durbin- Watson
aPredictor: (constant), fasting C-peptide/glucose ratio. ^bPredictor: (constant), fasting C-peptide/glucose ratio, glucose. ^cPredictor: (constant), fasting C-peptide/glucose ratio, glucose, body weight. ^dPredictor: (constant), fasting C-peptide/glucose ratio, glucose, body weight, FEI.
1	0.974a	0.950	0.949	96.09569	0.950	2,884.299	0.000
2	0.994^b	0.987	0.987	48.64369	0.038	445.099	0.000
3	0.994^c	0.988	0.988	47.50930	0.001	8.345	0.004
4	0.994^d	0.988	0.988	46.56880	0.001	7.161	0.008	2.031

Table 4. Stepwise Multiple Regression Between C-Peptide and Known Predictors of Dysmetabolic Disease in Patients With Polycystic Ovary Syndrome

Model

R²

Adjusted R²

Standard error of estimate

Change statistics

Sig. F change

Durbin- Watson

R² change

F change

aPredictor: (constant), fasting C-peptide/glucose ratio. ^bPredictor: (constant), fasting C-peptide/glucose ratio, glucose. ^cPredictor: (constant), fasting C-peptide/glucose ratio, glucose, body weight. ^dPredictor: (constant), fasting C-peptide/glucose ratio, glucose, body weight, FEI.

0.974a

0.950

0.949

96.09569

0.950

2,884.299

0.000

0.994^b

0.987

48.64369

0.038

445.099

0.000

0.994^c

0.988

47.50930

0.001

8.345

0.004

0.994^d

0.988

46.56880

0.001

7.161

0.008

2.031