Page 96 - The clinical aspects and management of chronic migraine Judith Anne Pijpers

Chapter 5
Figure 1. Study design
Blinded phase (weeks 0 - 12): Medication withdrawal therapy plus maximal or minimal intervention, randomized by a centralized schedule using a design with blocks of four to eight patients, stratified for gender and treatment allocation in the drug trial. Hence, in both groups, half of the patients received active drug Botulinum toxin A (BTA) and half of the patients received placebo drug (saline + low dose BTA).15
Regular care (weeks 12 - 48): Advice to restrict use of acute medication (on ≤ 4-8 days per month) to prevent relapse into medication overuse, and, if necessary, initiation of prophylactic treatment. Patients who succeeded to withdraw, but still suffered from chronic migraine, could receive open label drug (BTA) as prophylactic treatment. Regular care typically comprises 4-8 outpatient contacts per year by the treating physician.
Randomization and masking of intervention
According to a centralized randomization schedule, patients were randomized 1:1 to receive either maximal or minimal behavioral intervention by a headache nurse, using blocks of four to eight patients, stratified for sex and the allocated treatment in the drug trial, ensuring that half of the patients in each group received BTA. Patients were unaware of the existence of the two treatment arms, as this study was concealed within this drug trial studying BTA, guaranteeing blinding of patients. As both maximal and minimal behavioral intervention are interventions without any risk of harm, both fulfilling standard care for medication withdrawal, and patients were informed that the data of the CHARM study was supposed to be analyzed for a variety of research questions, this construction was approved by the local and national ethical committees. Treating physicians and observers were blinded to treatment allocation and did not have access to the randomization schedule.
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