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Table 1 VOC frequency studies

From: A systematic literature review of frequency of vaso-occlusive crises in sickle cell disease

Study identifier

Country

N

Mean age

VOC definition

# of reported VOCs/year

Mean

SD

Range

IQR

Le et al. [16]

Belgium

139

21a

Hospitalization

0/100 PYa,b

     

29.6/100 PYa,c

   

Donaldson et al. [22]

Jamaica

50

18.5

NR

5.63/100 PYd

Upadhye et al. [23]

India

75

NR

NR

9.7/100 PY

Lamarre et al. [24]

French West Indies

49

11.9

Hospitalization

0.26e

0.39

  

44

11.4

 

0.41f

   

Willen et al. [25]

Multiple

165

10

Hospitalization

0.27a

Asnani et al. [26]

Jamaica

8504

NR

Healthcare visit (OP or IP) to center; recorded in database

0.4

0.7

DeBaun et al. [27]

U.S

159

9a

Hospitalization and treatment with opioids

0.46a

Boyd et al. [28]

U.S

242

0.25

Healthcare visit (OP or IP) to clinic

0.47g

Rezende et al. [29]

Brazil

461

9.2

Healthcare visit (OP or IP) to center

51/100 PY

48.9–53.4

Schuchard et al. [30]

U.S

35

0.6

Healthcare visit (OP or IP) to center

0.15h

  

13

1.6

 

0.9i

   
  

17

3.0

 

0.52j

   

Ceglie et al. [31]

Italy

16

10.5

Hospitalization at study center

0.6k

  

23

10.3

 

1.6l

   

Inati et al. [32]

Lebanon

335

8.6

Hospitalization

0.6

0.6

0.04–2.4

Jain et al. [33]

India

833

NR

Healthcare visit (OP or IP) to center

64/100 PY

Lettre et al. [34]

Multiple

1275

14.5

NR

0.7/PY

1.4

Nimgaonkar et al. [35]

India

137

14a

NR

0.7

Barner et al. [36]

U.S

1190

NR

Healthcare visit (OP, IP, or ED)

4.1/5 year study period

5

Willen et al. [37]

U.S

197

11

Hospitalization and treatment with opioids

0.86

Yates et al. [38]

Multiple

15

9.6a

Hospitalization

1.18a,m

0–1.94

Joseph et al. [39]

U.S

16,092

36.7

Healthcare visit (OP, IP, or ED); Texas Medicaid claims

1.2

Leleu et al. [40]

France

157

33a

Healthcare visit (OP, IP, or ED); French National Health Data System

1.9n

Janecek et al. [41]

U.S

66

38.8

Healthcare visit (OP, IP, or ED)

2o

Dave et al. [42]

India

404

19

Healthcare visit (OP or IP) to care system

2.77

Madu et al. [43]

Nigeria

126

24.9

Healthcare visit (OP or IP) to center

3

4.8

Osunkwo et al. [18]

Multiple

2145

NR

Self-reported (patient survey; hospitalization, ED, managed at home)

3a

2–6

Latremouille-Viau et al. [44]

U.S

18,287

28.5

Healthcare visit (OP, IP, or ED); Medicaid and Medicare claims

3.1p

 

  

15,431

48.2

 

3.4q

   

Shah et al. [45]

U.S

8521

32.9

Healthcare visit (OP, IP, or ED); Medicaid claims

3.31

Desai et al. [46]

U.S

44,033

15.7

Healthcare visit (≥ 2 OP, or ≥ 1 IP, or ED); Medicaid claims

3.71

James et al. [19]

Multiple

1513

24.1

Self-reported (patient survey; hospitalization, ED, managed at home)

5.2

Alsultan et al. [47]

Saudi Arabia

159

17.8

Hospitalization for > 48 h

5.6

5.7

0–36

Andemariam et al. [20]

U.S

384

30.1

Self-reported (patient survey; hospitalization, ED, managed at home)

7.1

5.7

Bronte-Hall et al. [48]

U.S

149

33.2a

Healthcare visit (OP or IP) to center

10.4

McClish et al. [21]

U.S

87

33.6

Self-reported (patient diary)

6.0/6 monthsk

  

139

34.5

 

6.8/6 monthsl

   

Shome et al. [17]

Bahrain

51

29.6

Healthcare visit (OP or IP) to center

18.2m

17.5

  1. ED emergency department, IP inpatient, IQR interquartile range, NR not reported, OP outpatient, PY patient-year, SCD sickle cell disease, SD standard deviation, VOC vaso-occlusive crisis
  2. aMedian reported
  3. bAdults study arm
  4. cAdolescents study arm
  5. dCases arm, patients with steady-state HBF levels below 1%
  6. eHbSC study arm
  7. fHbSS study arm
  8. gNon-asthmatic study arm
  9. hPatients who started hydroxyurea between 5 months and 1 year of age
  10. iPatients who started hydroxyurea between 1 and 2 years of age
  11. jPatients who started hydroxyurea between 2 and 5 years of age
  12. kMale study arm
  13. lFemale study arm
  14. mPre-hydroxyurea therapy study arm
  15. nPatients who had at least 2 inpatient stays for SCD diagnosis/chronic long-term SCD, or a reimbursement for Siklos/Hydrea
  16. oPre-assessment study arm
  17. pMedicaid claims study arm
  18. qMedicare claims study arm