Table 2 Major research streams determined by document co-citation output

Cluster #1

Child health

- child health

- economic evaluation

- systematic review

- birth weight

- body weight

S

653

[21, 22]

322

[23]^a

24.82

2005–2014

[24]

0.03

[25]

31

SS

0.838

[23]^a

171

[26]^a

24.68

2014–2021

[27]

0.02

[28]

27

MY(ref)

2002

[26]^a

161

[27]

17.54

1999–2007

[29]

0.02

[30]

17

YR(ref)

1964–2020

[31]

131

[32]^a

16.18

2017–2021

[31]

0.02

[33]

16

MY(citing)

2013

[34]

125

[35]^a

16.14

1990–2011

[36]

0.02

[37]

15

YR(citing)

1993–2021

[38]

117

[39]

14.39

2014–2018

[21, 22]^a

0.02

[40]

15

[24]

81

[41]

12.98

1993–2007

[42]

0.02

[43]

15

[32]^a

80

[44]

12.54

2015–2017

[45]

15

[46]

78

[47]

12.45

2015–2021

[48]

14

[35]^a

65

[49]

12.25

2015–2021

[50]

14

[51]

64

12.16

2001–2010

[52]

14

[53]

14

Cluster #2

Economic Evaluation (overall)

-economic evaluation

-information analysis

-economic model

-ispor-smdm modeling

-cost effectiveness

S

580

[54]^a

377

[54]^a

39.12

2008–2017

[55]^a

0.03

[56]

39

SS

0.787

[57]^a

218

38.01

2010–2014

[58]

0.03

[59,60,61,62]

28

MY(ref)

2005

[63]

151

[64]

30.28

1999–2008

[64]

0.02

[65, 66]

26

YR(ref)

1954–2020

[67]

144

[67]

24.37

1999–2011

0.02

[68]

24

MY(citing)

2012

[69]

127

[70]

21.14

2017–2021

[71]

0.02

[65, 66]

22

YR(citing)

1990–2021

[72]

114

18.96

2006–2011

[69]

0.02

[72]

21

[64]

109

[73]

18.38

1995–2005

[63]

0.02

[74]

20

[75]

106

[72]

17.92

2002–2012

[76]

0.02

[77]

18

101

[59,60,61,62]

17.39

2014–2021

[78]

0.02

[79]

17

[80]

94

[81]

0.02

Cluster #3

Health-related quality of life

- health-related quality- achievement goal

- 5d-5 l value

- preference-based measure

- eq-5d health state

- economic cost

S

499

[82]

421

[83, 84]^a

47.63

2015–2021

[85]

0.03

[86]

29

SS

0.847

[83, 84]^a

326

41.85

2016–2021

[87]

0.03

[88]

24

MY(ref)

2006

[89]

271

[90]

38.24

2017–2021

[91]

0.02

[92]

24

YR(ref)

1961–2020

240

37.06

2016–2021

[93]

0.02

[94]

23

MY(citing)

2014

[95]

209

[96]

32.34

2018–2021

[97]

0.02

[96]

23

YR(citing)

1999–2021

[90]

175

[98]

24.96

2016–2021

[99, 100]

0.02

[101]

23

157

[102]

24.61

2017–2021

[82]

0.02

[103]

23

142

[59,60,61,62]

24.08

2016–2021

0.02

[104]

22

[85]

133

[105]^a

20.32

2011–2017

[95]

0.02

[106]

22

[97]

129

[107]

0.02

[108]

0.02

Cluster #4

Adverse Selection

- adverse selection

- risk selection

- moral hazard

- economic evaluation

S

379

[109]

97

[109]

16.01

1990–2012

[109]

0.06

[110]

24

SS

0.926

[111]

81

[112]

12.68

2017–2021

[113]

21

MY(ref)

1998

[114]

78

[115]

12.06

1998–2007

[116]

15

YR(ref)

1950–2019

[117]

47

[118]

9.84

2016–2021

[119]

15

MY(citing)

2011

[120]

42

[121]

9.82

2017–2021

[122]

14

YR(citing)

1990–2021

[123]

40

[124]^a

9.77

2015–2018

[125]

14

[121]

40

[126]^a

9.6

2017–2021

[127]

14

[115]

40

[120]

8.84

2015–2021

[128]

13

[129]

36

[130]

8.05

2018–2021

[131]

13

[132]

36

Cluster #5

Health care expenditure

- health care expenditure

- hospital cost

- public health expenditure

S

326

[133]

166

[134]

18.46

1990–2009

[135]

0.06

[113]

15

SS

0.89

[136]

110

[137]^a

18.42

2012–2020

[134]

0.04

[138]

12

MY(ref)

1995

[139]

91

[140]

16.86

2000–2010

[139]

0.03

[141]

12

YR(ref)

1957–2018

[142]

80

[143]

14.29

2010–2015

[144]

0.02

12

MY(citing)

2008

[140]

77

[145]

12.17

2000–2011

[146]

0.02

[147]

12

YR(citing)

1990–2020

[144]

74

[144]

12.14

1991–2008

[148]

0.02

[149]

11

[150]^a

65

[151]

11.88

1990–2000

[142]

0.02

[152, 153]

10

[134]

59

[134]

9.69

1994–2005

[154]

0.02

[155]

10

[145]

59

[156]

8.69

2014–2018

[152, 153]

10

[157]

8.62

2000–2009

[158]

10

[159]

10

Cluster #6

Patient preference

- patient preference

- patients preference

- using best-worst scaling

- contingent valuation studies

S

317

[160]

107

[161]

23.35

2001–2007

[162]

0.02

[163]

30

SS

0.92

[164]

106

[165]

20.92

2014–2021

0.02

[166]

23

MY(ref)

2003

[167]

90

[168]

20.85

2016–2021

[169]

0.02

[170]

23

YR(ref)

1966–2020

[165]

89

[164]

19.72

2013–2021

[171]

19

MY(citing)

2012

[172]

81

[173]

18.63

2001–2007

[174]

18

YR(citing)

1996–2021

[169]

76

[175]

16.08

2016–2021

[176]

18

[161]

66

[177]

16.04

1998–2009

[178]

17

[179]^a

64

[180]^a

15.96

1996–2003

[181]

17

[182]^a

60

[183]^a

15.65

1996–2008

[184]

17

[182]

15.33

2011–2016

Cluster #7

Influenza vaccine

- influenza vaccination

- economic evaluation reporting standard

- consolidated health

- pharmacoeconomic studies

- antidepressant prescribing

S

289

[185]

152

[186]

14.3

1996–2005

[187]

0.04

[188, 189]

26

SS

0.894

[190]

46

[191]

13.21

1997–2001

[192]

0.03

[188, 189]

23

MY(ref)

1994

[187]

34

[187]

12.15

1995–2002

[185]

0.03

[193]

23

YR(ref)

1979–2013

[194]

33

11.45

1996–2000

[186]

0.02

[59,60,61,62]

18

MY(citing)

1999

[195]

31

[196]

10.93

1996–2003

[197]

0.02

[59,60,61,62]

18

YR(citing)

1994–2019

[186]

29

[198]

10.84

1996–2000

[59,60,61,62]

18

[191]

22

10.04

1994–1998

[59,60,61,62]

18

[199]

21

[200]

9.87

1997–2000

[201]

18

[196]

20

[202]

9.25

1997–2000

[200]

17

[203]

17

Cluster #8

Prospect theory

- prospect theory

- person trade-off

- internal consistency

- individual preference

- standard gamble

S

286

[204, 205]

166

[83, 84]^a

42.4

2017–2021

[206]

0.03

[207]

33

SS

0.886

[208]

125

[209]^a

31.16

1992–1999

[208]

0.03

[210]

30

MY(ref)

1991

[83, 84]^a

105

[204, 205]

23.23

1991–2009

[211]

0.03

[212]

24

YR(ref)

1951–2018

[209]^a

61

[213]

16.07

1992–2005

[204, 205]

0.02

[214]

18

MY(citing)

2004

[215]

59

[216]

14.75

1999–2005

[99, 100]

0.02

[217]

18

YR(citing)

1991–2020

[218]

52

[218]

14.6

1997–2005

[219]

18

[216]

51

[220]

12.85

1999–2009

[221]

16

[213]

47

[222]

12.31

1997–2006

[223]

16

[99, 100]

44

[224]

11.58

1992–1998

[225]

16

[220]

43

[226]

11.02

1992–2000

Cluster #9

Economic Evaluation (elements)

- cost-effectiveness threshold

- cost-effectiveness analysis

- life year

- ispor special task force report

- stroke prevention

S

256

[227]^a

584

[227]^a

40.93

1998–2009

[217]

0.05

[228]

23

SS

0.89

[229]

96

[230]

26.61

2016–2021

[229]

0.02

[231]

20

MY(ref)

2007

[230]

81

[229]

24.63

1994–2007

[232]

0.02

[233]

12

YR(ref)

1957–2020

[232]

81

[234]

20.6

2018–2021

[235]

0.02

[236]

12

MY(citing)

2013

[237]

77

19.35

2010–2014

[235]

11

YR(citing)

1992–2021

[238]

70

[239]

17.07

2016–2021

[240]

11

[241]

67

[242]^a

13.93

2017–2021

[243]

11

[244]

61

[241]

13.19

1998–2008

[234]

10

[245]

57

[246]

13.02

2007–2012

[247]

9

[248]

57

[248]

12.53

2006–2013

Cluster #10

Medicaid expansion

- medicaid expansion

- affordable care act

- health insurance

- economic evaluation

- health insurance coverage

S

252

[249]

188

[250]

23.54

2015–2021

[251]

0.04

[28]

18

SS

0.923

[251]

160

[252]

20.36

2016–2021

[253]

15

MY(ref)

2006

[254]

117

[255]

14.56

2014–2021

[256]

15

YR(ref)

1972–2020

[250]

85

[257]

12.92

2015–2021

[258]

14

MY(citing)

2016

63

[259]

11.89

2015–2021

[260]

13

YR(citing)

1990–2021

[252]

62

[261]

11.62

2015–2021

[262]

13

[255]

62

[263]

11.6

2015–2018

[264]

12

[265]

52

[266]

11.59

2017–2021

[267]

12

[268]

50

[257]

50

Cluster #11

Migraine

- informal care

- long-term care insurance

- autism spectrum disorder

- life outcome

- formal care

S

169

[19, 20]

128

[19, 20]

49.8

2018–2021

[269]

0.02

[270]

23

SS

0.915

[271]

48

[272]^a

9.56

2002–2009

[271]

0.02

[273]

21

MY(ref)

2008

46

9.5

2017–2017

[274]

18

YR(ref)

1979–2020

[275]

41

[276]

9.11

2015–2017

[92]

18

MY(citing)

2016

[276]

36

[277]

8.69

2008–2016

[170]

18

YR(citing)

2007–2021

[278]

36

[279]

8.57

2015–2021

[231]

17

[280]

31

[281]

7.85

2015–2021

[94]

16

[272]^a

31

[278]

7.69

2015–2018

[282]

15

[279]

31

[277]

31

Cluster #12

Informal care

- multinational investigation

- subcutaneous sumatriptan

- workplace productivity

- osteoporotic fracture

- hypertensive patient

S

161

[283]

112

[284]

10.7

2009–2014

[285]

0.02

[286]

19

SS

0.939

[287]

26

9.45

1998–2004

[287]

0.02

[288]

18

MY(ref)

1998

[284]

25

8.45

2005–2011

[283]

0.02

[289]

17

YR(ref)

1967–2016

[290]

20

[291]

7.94

2000–2005

[292]

14

MY(citing)

2008

[293]

20

[285]

7.21

1996–2003

[294]

14

YR(citing)

1997–2021

[295]

19

[296]

6.97

1997–2004

[297]

11

19

[295]

6.91

2007–2014

[298]

10

17

[299]

6.89

2007–2013

[300]

10

[285]

17

[287]

6.53

2000–2013

[301]

10

Cluster #13

HIV infection

- mg bid

- treatment-experienced hiv-infected adult

- hiv infection

- belgium italy sweden

- 1-infected adult

S

117

[302]

18

[302]

9.56

1994–1999

[303]

0.04

[304, 305]

52

SS

0.987

[303]

12

[306]

5.16

2006–2010

[302]

0.03

[304, 305]

52

MY(ref)

2001

[307]

11

[308]

4.55

1996–2000

[309]

43

YR(ref)

1981–2010

[308]

11

[310, 311]

42

MY(citing)

2006

[306]

10

[312]

25

YR(citing)

1998–2010

[313]

10

[314]

22

[315]

9

[310, 311]

21

[316]

9

[317]

19

Cluster #14

Coronary heart disease

- coronary heart disease

- hmg-coa reductase inhibitor

- treating dyslipidaemia

- using national cholesterol education program

- lipid management protocol

S

113

28

[318]

13.7

1997–2005

[319]

28

SS

0.957

[318]

27

12.12

1997–2005

[320]

25

MY(ref)

1995

[321]

17

[321]

8.62

1997–2005

[322]

25

YR(ref)

1975–2005

[323]

16

[323]

7.98

1998–2006

[324]

24

MY(citing)

2002

[325]

14

[326]

6.85

1998–2005

[327]

18

YR(citing)

1997–2007

[326]

13

[328]

6.3

2005–2008

[329]

17

[330]

12

[325]

6.19

2003–2010

[331]

14

[332]

12

[333]

6.12

2005–2007

[334]

14

[330]

5.99

1998–2006

[335]

14

[336]

4.82

1997–2004

[337]

4.06

1997–2005

Cluster #15

Congestive heart failure

- congestive heart failure

- of-life evaluation

- needs-based quality

- life instrument

- ace inhibitor

S

108

[338]

23

[338]

12.47

1996–2000

[207]

29

SS

0.98

[339]

7

[340]

4.34

1996–1999

[341]

20

MY(ref)

1988

[340]

7

4.34

1996–1999

[342]

11

YR(ref)

1951–2004

7

[339]

4.03

1999–2004

[343]

10

MY(citing)

1998

[344]

6

[345]

3.92

1990–1996

[346]

9

YR(citing)

1991–2004

[345]

6

3.83

1996–1998

[347]

9

[348]

6

[344]

3.72

1998–2001

[349]

9

6

[348]

3.68

2001–2004

[350]

8

Cluster #16

Rheumatoid arthritis

- rheumatoid arthritis

- eastern european countries

- anti-tumour necrosis factor-alpha drug

- economic decision

- including adverse drug event

S

101

[351]

25

[351]

9.83

2012–2015

[56]

32

SS

0.983

[352]

18

[352]

6.25

2004–2010

[353]

30

MY(ref)

2003

[354]

11

[355]

5.09

2004–2010

[356]

29

YR(ref)

1980–2017

[357]

11

[76]

4.72

2012–2014

[358]

20

MY(citing)

2009

[76]

11

[359]

3.84

2004–2008

[360]

18

YR(citing)

2004–2020

[361]

11

[362]

14

[355]

11

[363]

14

[364]

13

Cluster #17

Supplier Inducement

- supplier inducement

- public-health care system

- fee descriptor

- multilevel discrete choice model

- treatment choice

S

88

[365]^a

14

[366]

5.44

1993–1999

[367]

0.02

[368]

12

SS

0.977

[369]

13

[370]^a

5

1994–2002

[371, 372]

10

MY(ref)

1986

[367]

9

[373]

4.62

1990–2000

[374]

9

YR(ref)

1970–2001

[370]^a

9

[368]

4.46

1999–2007

[371, 372]

9

MY(citing)

1997

[366]

9

[375]

4.45

1998–2000

[375]

8

YR(citing)

1990–2007

[368]

9

[365]^a

4.43

1991–2001

[376]

8

[373]

8

[367]

4.21

1990–2005

[377]

8

[378]

3.82

2001–2003

[379]

8

[380]

3.65

1994–1999

[381]^a

3.51

2007–2009

Cluster #18

Psychotropics

- long-acting risperidone

- economic outcome

- antipsychotic agent

- long-acting risperidone injection

- conventional depot formulation

S

87

[382]

28

[382]

9.81

1998–2006

[383]^a

0.03

[384, 385]

16

SS

0.985

[386]

18

[386]

7.46

2008–2010

[382]

0.02

[384, 385]

15

MY(ref)

1996

[383]^a

13

[383]^a

7.02

1995–2003

[387]

13

YR(ref)

1967–2007

[388]

9

[388]

4.93

2004–2008

[389]

13

MY(citing)

2004

[390]

7

[391]

3.61

1998–2002

[392]

12

YR(citing)

1998–2008

[393]

6

[394]

12

[395]

6

[396]

12

[397]

6

[398]

11

[391]

6

[399]

11

[400]

6