Outcomes
headaches, headache
In the RCT, four primary outcomes were considered. Three were based on weekly text message (SMS) reports from the participating children and their parents: The frequency of headaches (Number of days with headache per week), the headache intensity on a numerical rating scale (NRS) from 0 to 10, and the number of headache pills per week. A 4-weeks pre-treatment period was compared with the final 4 weeks of the study period (week 14–17) at the individual level by computing change scores. The fourth primary outcome was the global perceived effect (GPE) after 4 months, based on a final SMS.Due to reporting issues with respect to the number of pills, this variable could only be analyzed at the level of yes/no per week, and no difference between the intervention groups was observed. Also, for headache intensity, no difference was found. In contrast, a significant difference was found with respect to the change in the frequency and the global perceived effect. The average change in number of days with headache from baseline was − 0.813 in the chiropractic manipulation group and − 0.406 in the sham manipulation group, i.e., chiropractic manipulation decreased the number of days with headache on average by 0.41. The GPE was assessed on a 7-point scale with low values indicating a favorable outcome. The average numbers were 2.62 and 3.24 for the chiropractic manipulation group and the sham group respectively, i.e., the chiropractic manipulation improved the GPE on average by 0.62 [