Table 1 Numbers of participants and of those with missing data for each variable

N with migraine

1,856

3,192

870

1,882

Numbers missing data

Lost productivity

 HALT questions 1 + 2

136

664

42

172

 HALT questions 3 + 4

578

310

46

115

Disability factors

 F only

17

10

2

2

 D only

88

156

5

26

 I only

4

5

3

17

 F + D

5

10

1

4

 F + I

0

0

0

1

 D + I

2

1

3

10

 F + D + I

0

0

0

1

 Total with missing disability data of whom also missing HALT 1 + 2 data^a and of whom also missing HALT 3 + 4 data^a

116

182

14

61

11

37

2

18

35

32

2

14

 Final N in HALT 1 + 2 analyses^a

1,615 (87.0%)

2,383 (74.7%)

816 (93.8%)

1,667 (88.6%)

(1,856 – [136 + (116–11)])

(3,192 – [664 + (182–37)])

(870 – [42 + (14–2)])

(1,882 – [172 + (61–18)])

 Final N in HALT 3 + 4 analyses^a

1,197 (64.5%)

2,732 (85.6%)

812 (93.3%)

1,720 (91.4%)

(1,856 – [578 + (116–35)])

(3,192 – [310 + (182–32)])

(870 – [46 + (14–2)])

(1,882 – [115 + (61–14)])