Secondary outcomes, diary data analysed by linear regression
| Outcome | ICC (%) | Crude | Adjusted* | ||
|---|---|---|---|---|---|
| Coeff (95% CI) | p Value | Coeff (95% CI) | p Value | ||
| Change in headache days/4 weeks | 63.7 | −1.5 (−4.8 to 1.7) | 0.34 | −1.4 (−4.8 to 1.9) | 0.38 |
| Change in medication days/4 weeks | 24.2 | −9.8 (−13.1 to −6.6) | <0.001 | −9.5 (−12.8 to −6.2) | <0.001 |
| Change in Visual Analogue Scale | 35.4 | −8.4 (−20.7 to 4.0) | 0.16 | −8.8 (−21.6 to 4.0) | 0.17 |
| Change in headache index | 7.2 | −300 (−574 to −25) | 0.03 | −304 (−590 to −18) | 0.04 |
Coeff, regression coefficient in linear mixed model, showing average difference (number of days) between business as usual (coded as 0) and brief intervention (coded as 1) groups; ICC: intraclass correlation coefficient.
*Regression coefficients adjusted for age, gender and co-occurrence of migraine.