Table 4

Number of headache days

Time point

Summary

Sham

True

IRR (95% CI)*

P-value

12 weeks**

N

Median (IQR)

69

20 (12 to 29)

69

19 (8 to 28)

1.15 (0.94 to 1.41)

1.17 (0.96 to 1.42)

0.18

0.11

4 weeks

N

Median (IQR)

78

8 (5 to 12)

78

7 (4 to 10)

1.23 (1.01 to 1.50)

1.24 (1.02 to 1.50)

0.04

0.03

*Values in italics are the results from using multiple imputation to account for the missing data

**Primary outcome

Mitchell et al. Nutrition Journal 2011 10:85   doi:10.1186/1475-2891-10-85