We have updated the migraine prevention guideline of the Canadian Headache Society from 2012, as there are new therapies available, and additionally, we have provided guidelines for the prevention of chronic migraine, which was not addressed in the previous iteration.

We undertook a systematic review to identify new studies since the last guideline. For studies identified, we performed data extraction and subsequent meta-analyses where possible. We composed a summary of the evidence found and undertook a modified Delphi recommendation process. We provide recommendations for treatments identified and additionally expert guidance on the use of the treatments available in important clinical situations.

We identified 61 studies that were included in this evidence update and identified 16 therapies we focused on. The anti-calcitonin gene-related peptide (CGRP) agents were approved by Health Canada between 2018 and 2024 and provide additional options for episodic and chronic migraine prevention. We also summarize evidence for the use of propranolol, topiramate and onabotulinumtoxinA in addition to anti-CGRP agents as treatments for chronic migraine. We have downgraded topiramate to a weak recommendation for use and gabapentin to a weak recommendation against its use in episodic migraine. We have weakly recommended the use of memantine, levetiracetam, enalapril and melatonin in episodic migraine.

Based on the evidence synthesis, we provide updated recommendations for the prevention of episodic and chronic migraine utilizing treatments available in Canada. We additionally provided expert guidance on their use in clinical situations.

PREDICT was a Canadian, multicenter, prospective, observational study in adults naïve to onabotulinumtoxinA treatment for chronic migraine (CM). We descriptively assess health resource utilization, work productivity, and acute medication use.

OnabotulinumtoxinA (155–195 U) was administered every 12 weeks over 2 years (≤7 treatment cycles). Participants completed a 4-item health resource utilization questionnaire and 6-item Work Productivity and Activity Impairment Questionnaire: Specific Health Problem V2.0. Acute medication use was recorded in daily headache diaries. Treatment-emergent adverse events were recorded throughout the study.

A total of 197 participants were enrolled, and 184 received ≥1 treatment with onabotulinumtoxinA and were included in the analysis. Between baseline and the final visit, there were decreases in the percentage of participants who reported headache-related healthcare professional visit(s) (96.2% to 76.8%) and those who received headache-related diagnostic testing (37.5% to 9.9%). Reductions from baseline were also observed in the mean number of headache-related visits to an emergency room/urgent care clinic (2.5 to 1.4) and median headache-related hospital admissions (4.0 to 1.0). OnabotulinumtoxinA improved work productivity and reduced the mean (standard deviation) number of hours missed from work over a 7-day period (6.1 [9.7] to 3.0 [6.8]). Mean (standard deviation) acute medication use decreased from baseline (15.2 [7.6] to 9.1 [6.5] days). No new safety signals were identified.

Real-world evidence from PREDICT demonstrates that onabotulinumtoxinA treatment for CM in the Canadian population reduces health resource utilization and acute medication use and improves workplace productivity, supporting the long-term benefits of using onabotulinumtoxinA for CM.

The PREDICT study assessed real-world, long-term health-related quality of life in adults with chronic migraine (CM) receiving onabotulinumtoxinA.

Canadian, multicenter, prospective, observational study in adults naïve to onabotulinumtoxinA for CM. OnabotulinumtoxinA (155–195 U) was administered every 12 weeks over 2 years (≤7 treatment cycles). Primary endpoint: mean change in Migraine-Specific Quality of Life Questionnaire (MSQ) at treatment 4 (Tx4) versus baseline. Secondary endpoints: mean change in MSQ at final visit versus baseline, and headache days.

184 participants (average age 45 years; 84.8% female; 94.6% Caucasian) received ≥1 onabotulinumtoxinA treatment; 150 participants completed 4 treatments (1 year) and 123 completed all 7 treatment cycles (2 years). Mean (SD) onabotulinumtoxinA dose per treatment cycle was 171 (18) U and treatment interval was 13.2 (1.8) weeks. Baseline mean (SD) 20.9 (6.7) headache days/month decreased (Tx1: −3.5 [6.3]; Tx4: −6.5 [6.6]; p < 0.0001 versus baseline). Mean (SD) increased from baseline in MSQ at Tx4 (restrictive: 21.5 [24.3], preventive: 19.5 [24.7], emotional: 22.9 [32.9]) and the final visit (restrictive: 21.3 [23.0], preventive: 19.2 [23.7], emotional: 27.4 [30.7]), exceeding minimal important differences (all p < 0.0001). Seventy-seven (41.8%) participants reported 168 treatment-emergent adverse events (TEAEs); 38 TEAEs (12.0%) were considered treatment-related. Four (2.2%) participants reported six serious TEAEs; none were considered treatment-related. No new safety signals were identified.

Real-world evidence from PREDICT demonstrates that onabotulinumtoxinA for CM in Canada improved MSQ scores and reduced headache frequency and severity, adding to the body of evidence on the long-term safety and effectiveness of onabotulinumtoxinA for CM.

There is evidence that headache response rates may be higher if triptans are used early when a migraine attack is still mild, as compared to when it is treated after pain has reached moderate or severe intensity.

In this randomized, double blind, placebo controlled, parallel group clinical trial, 361 patients took either placebo, sumatriptan 50 mg, or sumatriptan 100 mg in a single attack study. The primary outcome measure was pain-free status at two hours.

In the intention to treat group, two hour pain free rates were 16%, 40%, and 50% in the placebo group, sumatriptan 50 mg group, and the sumatriptan 100 mg group respectively (p<0.001, active treatment groups vs. placebo).

Both sumatriptan 50 mg and 100 mg were significantly superior to placebo for the pain-free end point at two hours. The pain-free response rates in this trial where sumatriptan was taken while the headache was still mild were generally higher than in older clinical trials where headache was treated after reaching a moderate or severe intensity.

To examine demographic characteristics and clinical features of headache patients referred to neurologists specializing in headache in Canada.

Demographic and clinical data were collected at the time of consultation for 865 new headache patients referred to five headache-specialty clinics in Canada. The Headache Impact Test (HIT-6) and Migraine Disability Questionnaire (MIDAS) were used to measure headache impact and disability. Data were analyzed as part of the Canadian Headache Outpatient Registry and Database (CHORD) Project.

The average age of the patients was 40 years and the majority were female (78%). Most were employed either full time (49%) or part time (13%). The majority of patients were diagnosed with either migraine or tension-type headache (78%). Over a third of patients experienced headache every day, and half had experienced a headache in the previous month which was of severe intensity. Most (80%) scored in the “very severe” category of the HIT-6 and over half (55%) were severely disabled as measured by the MIDAS.

Patients referred to headache specialists in Canada are severely disabled by their headache disorders. These patients are in the most productive phase of their lives in terms of age and employment. It is important to provide the best available treatment to headache patients in order to minimize the disability and impact of their headache disorders.

Patients with chronic migraine and medication overuse are significant consumers of health care resources.

To determine whether botulinum toxin type A prophylaxis reduces the cost of acute migraine medications in patients with chronic migraine and triptan overuse.

In this multicenter, open-label study, patients with chronic migraine (≥15 headache days/month) who were triptan overusers (triptan intake ≥10 days/month for ≥3 months) received botulinum toxin type A (95-130 U) at baseline and month three. Headache (HA) frequency and medication use were assessed with patient diaries, and headache-related disability by means of the MIDAS and Headache Impact Test-6 questionnaires.

Of 53 patients enrolled (mean age ± standard deviation, 46.5 years ± 8.4; 47 [88.7%] females), 48 (90.6%) completed the study at month six. Based on headache diaries, significant (P≤0.0002) decreases from baseline were observed for days per month with headache/migraine, days with any acute headache medication use, days with triptan use, and triptan doses taken per month. A significant (P<0.0001) increase from baseline in headache-free days per month was also observed. Prescription medication costs for acute headache medications decreased significantly, including significant reductions in triptan costs (mean reduction of -C$106.32 ± 122.87/month during botulinum toxin type A prophylaxis; P<0.0001). At baseline, 78% of patients had severe disability (MIDAS score) and 86.8% had severe impact due to headache (HIT-6 scores); at month six, this decreased to 60% and 68%, respectively.

Botulinum toxin type A prophylactic therapy markedly decreased costs related to acute headache medication use in patients with chronic migraine and triptan overuse.