Table 4 Linear models for headache impact test 6
Outcome Variable: Headache impact test 6 (HIT-6) | ||||
|---|---|---|---|---|
Linear model Change in HIT-6 score. | Model 1 ~ Intervention | Model 2 ~ Intervention + Period | Model 3 ~ Intervention x Period | Model 4 ~ Period + Exposure time (Intervention nested in exposure time) |
Independent variable | Estimates (95%CI) | Estimates (95%CI) | Estimates (95%CI) | Estimates (95%CI) |
Intercept | 48.11 (46.45 to 49.77) | 48.81 (46.97 to 50.65) | 48.81 (46.97 to 50.65) | 48.81 (46.97 to 50.64) |
Intervention | −2.23 (−3.35 to −1.12) | −1.07 (−2.83 to 0.69) |  | - |
Period 1 |  | −0.73 (−2.39 to 0.93) | −1.06 (−2.84 to 0.73) | −1.01 (−2.68 to 0.67) |
Period 2 |  | −1.89 (−3.54 to −0.23) | −1.58 (−3.36 to 0.20) | −1.66 (−3.42 to −0.10) |
Period 3 |  | −1.34 (−3.28 to 0.61) | −1.31 (−2.34 to 1.02) | −1.76 (−3.97 to 0.45) |
Period 4 |  | −2.25 (−4.60 to 0.10) | −2.20 (−5.23 to 0.83) | −2.91 (−5.88 to 0.06) |
Intervention x Period 1 |  |  | −0.09 (−2.77 to 2.58) |  |
Intervention x Period 2 |  |  | −1.99 (−4.67 to 0.68) |  |
Intervention x Period 3 |  |  | −1.12 (−3.74 to 1.50) |  |
Exposure: 4 months |  |  |  | 0.24 (−2.19 to 1.70) |
Exposure: 8 months |  |  |  | −1.75 (−4.26 to 0.77) |
Exposure: 12 months |  |  |  | −0.63 (-−3.95 to 2.69) |
Exposure: 16 months |  |  |  | 0.77 (−3.31 to 4.86) |
Observations | 600 | 600 | 600 | 600 |
Log likelihood | −2066.0 | −2063 | −2062 | −2060 |
Akaike Information Criterion (AIC) | 4141 | 4143 | 4146 | 4145 |
Bayesian Information Criterion (BIC) | 4163 | 4183 | 4194 | 4198 |