Skip to main content

Table 1 Statistics on between-group meta-analyses regarding peripheral brain-derived neurotrophic factor levels in bipolar disorder

From: Peripheral brain-derived neurotrophic factor (BDNF) as a biomarker in bipolar disorder: a meta-analysis of 52 studies

Between-group

N of pairwise

Number of subjects

Meta-Analysis

Heterogeneity

BD

Controls

Hedges’ g

95 % CI

P value

I 2

Q

P value

Mania

          

 Mania vs. HC – all*

19

605

792

−0.57

−0.99

−0.14

0.010

92.07

239.69

0.001

 Mania vs. HC – drug-naïve or free*

6

175

186

−0.66

−1.14

−0.10

0.020

79.43

29.17

0.001

 Mania vs. HC – medicated

14

430

628

−0.54

−1.09

0.00

0.051

92.71

178.41

0.001

 Mania vs. HC – serum*

12

288

512

−0.97

−1.41

−0.53

0.001

86.45

81.12

0.001

 Mania vs. HC – plasma

6

206

188

−0.03

−0.98

0.95

0.951

94.73

94.94

0.001

 Mania vs. HC – plasma Barbosa excluded*

4

124

92

−0.72

−1.27

−0.17

0.001

70.06

10.02

0.018

 Mania vs. HC – whole-blood

2

144

153

0.12

−0.11

0.35

0.296

N/A

N/A

N/A

 Mania vs. HC – age-/sex-matched

14

488

551

−0.46

−0.99

0.07

0.073

93.09

202.40

0.001

 Mania vs. HC – not age-/sex-matched*

5

117

241

−0.84

−1.51

−0.18

0.042

86.17

28.90

0.001

Depression

          

 Depression vs. HC – all*

15

352

722

−0.93

−1.37

−0.50

0.001

87.88

107.27

0.001

 Depression vs. HC – drug-naïve or free*

3

47

210

−1.24

−1.88

−0.61

0.001

64.24

5.59

0.061

 Depression vs. HC – medicated*

13

305

534

−0.90

−1.59

−0.55

0.001

88.40

95.51

0.001

 Depression vs. HC – serum*

12

305

519

−0.72

−1.17

−0.27

0.002

87.53

114.67

0.001

 Depression vs. HC – plasma*

3

47

203

−1.94

−3.38

−0.49

0.009

90.25

20.51

0.001

 Depression vs. HC – age-/sex-matched*

10

245

501

−0.81

−1.29

−0.35

0.001

82.26

45.11

0.001

 Depression vs. HC – not age-/sex-matched*

5

107

221

−1.23

−2.30

−0.17

0.023

93.18

58.73

0.001

 Depression vs. HC – only BD type I*

12

219

369

−1.27

−1.80

−0.72

0.001

86.05

71.70

0.001

Euthymia

          

 Euthymia vs. HC – all

24

1598

1459

0.05

−0.13

0.24

0.569

81.19

122.29

0.001

 Euthymia vs. HC – serum

16

980

1022

−0.04

−0.16

0.17

0.689

86.67

69.66

0.001

 Euthymia vs. HC – plasma

8

618

437

0.26

−0.12

0.65

0.626

86.67

52.51

0.001

 Euthymia vs. HC – age-/sex-matched

16

658

733

0.02

−0.29

0.33

0.894

87.41

119.19

0.001

 Euthymia vs. HC – not age-/sex-matched

7

919

700

−0.06

−0.40

0.26

0.702

88.18

50.75

0.001

 Euthymia vs. HC – only BD type I

16

631

757

0.01

−0.30

0.32

0.319

87.00

115.43

0.001

 Euthymia vs. HC – only BD type II

2

31

48

−0.36

−1.46

0.73

0.729

81.66

5.45

0.001

Mixed State

          

 Mixed state vs. HC – all

3

44

169

0.09

−0.57

0.75

0.787

69.14

6.48

0.039

Moderators between-group

N of pairwise

Number of subjects

Meta-regression

Meta-regression

BD

Controls

Slope

95 % CI

P value

Intercept

Z

P value

Mania

          

 Age of BD patients – all*

19

605

792

0.07

0.02

0.13

0.005

−3.41

−3.27

0.001

 Age of BD patients – Barbosa excluded

17

523

696

0.03

−0.03

0.10

0.305

−1.93

−1.54

0.123

 Age of controls – all

19

605

792

0.04

−0.01

0.01

0.165

−2.14

−1.85

0.064

 Age difference(BD-HC) – all*

19

605

792

0.18

0.05

0.31

0.004

−0.61

−3.15

0.001

 Age difference(BD-HC) – Barbosa excluded

17

523

696

0.08

−0.07

0.24

0.295

−0.74

−3.86

0.001

 %Females (Patients)– all

17

579

760

0.01

−0.01

0.04

0.288

−1.33

−1.76

0.076

 %Females (HC) – all

17

579

760

0.00

−0.02

0.02

0.811

−0.75

−0.96

0.332

 Difference in %females (BD-HC) – all

17

579

760

0.02

−0.01

0.05

0.250

−0.54

−2.25

0.023

 Mean illness duration (years) – all

13

481

568

0.10

−0.01

0.21

0.070

−1.60

−2.27

0.023

 Sample size– all

19

605

792

0.00

−0.00

0.01

0.126

−1.09

−2.68

0.009

 YMRS scores – all*

17

583

750

−0.09

−0.15

−0.03

0.004

2.44

2.33

0.019

 YMRS scores – plasma*

5

192

176

−0.09

−0.16

−0.01

0.017

2.96

2.47

0.013

 YMRS scores – serum

10

247

421

−0.07

−0.15

0.00

0.052

1.63

1.18

0.235

Depression

          

 Age of BD patients – all

14

346

702

0.01

−0.04

0.06

0.681

−1.41

−1.21

0.225

 Age of controls – all

14

346

702

0.00

−0.06

0.07

0.996

−1.00

−0.76

0.445

 Age difference(BD-HC) – all

14

346

702

0.08

−0.07

0.24

0.262

−1.22

−3.99

0.001

 %Females (HC) – all

14

346

702

−0.00

−0.02

0.01

0.850

−1.03

−1.62

0.104

 %Females (Patients) – all

14

346

702

0.00

−0.01

0.01

0.782

−1.28

−2.30

0.020

 Difference in %females (BD-HC) – all

14

346

702

0.02

−0.01

0.05

0.193

−0.95

−3.68

0.001

 Mean illness duration (years) – all*

5

103

359

−0.14

−0.20

−0.07

0.001

−2.47

3.44

0.001

 Sample size – all

15

352

722

0.00

−0.00

0.01

0.070

−1.60

−3.74

0.001

 Year of publication – all

15

352

722

0.03

−0.14

0.19

0.726

−61.80

−0.35

0.722

 HDRS scores – all*

13

311

609

−0.23

−042

−0.04

0.018

4.40

1.93

0.053

 HDRS scores – serum

11

274

427

−0.12

−0.35

0.09

0.265

1.70

0.60

0.542

Euthymia

          

 Age of BD patients – all

24

1598

1459

−0.00

−0.02

0.02

0.950

0.11

0.23

0.831

 Age of controls – all

24

1598

1459

−0.00

−0.02

0.01

0.802

0.16

0.36

0.712

 Age difference(BD-HC) – all

24

1598

1459

0.02

−0.06

0.11

0.537

0.04

0.41

0.676

 %Females (HC) – all

23

1425

1197

0.00

−0.01

0.01

0.878

−0.03

−0.05

0.995

 %Females (Patients) – all

23

1425

1197

0.00

−0.01

0.02

0.690

−0.26

−0.40

0.684

 Difference in %females (BD-HC) – all

23

1425

1197

0.01

−0.02

0.03

0.555

0.06

0.68

0.495

 Number of mood episodes – all

5

206

220

0.01

−0.05

0.06

0.833

−0.24

−0.58

0.557

 Illness duration (years) – all

13

831

696

0.01

−0.02

0.05

0.577

0.01

0.01

0.992

 Illness duration (years) – excluding Barbosa 2010, 2012, 2013

10

739

575

−0.01

−0.04

0.02

0.496

0.13

0.48

0.630

 Sample size – all

24

1598

1459

−0.00

−0.01

0.01

0.530

0.12

0.85

0.390

  1. HDRS, Hamilton Depression Rating Scale; YMRS, Young Mania Rating Scale; CI, Confidence interval; BD, Bipolar disorder; HC, healthy controls; N/A, not applicable
  2. *p<0.05