Onabotulinumtoxin A Injections Statistically Improved Depression Scores in Patients With Chronic Migraine

Chronic migraine (CM) is frequently accompanied by clinical depression. Researchers from the Cleveland Clinic Headache Center and the Department of Quantitative Health Sciences and Neurological Institute Center for Outcomes Research and Evaluation recently published a study investigating the changes in depression when patients with CM are treated with onabotulinumtoxin A injections. The study retrospectively evaluated patient reported outcomes collected before and after at least 2 sessions of onabotulinumtoxin A injections. The study was conducted at a large Headache Center in the U.S. where patient reported outcome measures are routinely collected at each visit. The outcome measures included the Patient Health Questionnaire (PHQ9), Headache Impact Test (HIT6), Pain Disability Index (PDI), and European Quality of Life 5 Dimensions (EQ-5D). The primary outcome of the study was change in depression after onabotulinumtoxinA injections for CM.

PHQ9 detects and measures the severity of depression in the clinical setting using scores that range from 0 to 27. The scores can be interpreted as follows: 0-4 for no depression, 5-9 for mild depression, 10-14 for moderate depression, 15-19 for moderately severe depression and 20-27 for severe depression. It has been reported that a change of 5 points is a clinically meaningful change in depression, which suggests a significant response to treatment.

HIT6 is a screening and monitoring test that provides a global measure of headache impact in 6 domains. The 6 domains include social functioning, vitality, cognition, psychological distress, and severity of headache. Scores typically range from 26-78. Specifically, scores ≤49 represent little or no headache impact, scores between 50 and 55 represent some impact, scores between 56 and 59 represent substantial impact, and scores ≥60 indicate severe impact.

PDI provides a measure of how much pain interferes with an individual’s ability to function in 7 broad areas, which are categorized as voluntary activities and obligatory activities. The voluntary activities include family/home responsibilities, recreation, social activity, occupation, and sexual behavior. Obligatory activities include self-care and life support activities. Each item is rated from 0 (no interference) to 10 (total interference), which may total up to 70 points to suggest that pain greatly interferes with life’s activities.

EQ-5D covers 5 areas including mobility, self-care, usual/general activity, pain or discomfort, anxiety/depression, as well as general health of the patient. These areas are rated from 0 to 1, where 1 is the best quality of life.

The study included 429 adult patients with CM who had at least two rounds of onabotulinumtoxinA injections. Patients had to complete patient reported outcome measures on or before their first injection, and after their second injection, which could occur up to 1 year after the initial injection. A statistical analysis using paired t-tests on patients’ questionnaire scores before and after treatment were conducted to determine whether patients improved after onabotulinumtoxinA injections.

Results of the study showed that after onabotulinumtoxinA treatment, patients had statistically significant improvement on all measures, even after adjusting for multiple comparisons. When comparing points before and after 2 or more rounds of onabotulinumtoxinA injections, the magnitude of change was 0.7 points (P = .0078), which is a small but statistically significant change. The small change may be because most of the patients showed no symptoms of depression on their first visit or were not depressed at all. As depressive symptoms increased, there was a greater improvement in PHQ9. For example, patients with a score of 20 or higher (severe depression) improved by an average of 6.6 points (P = .004). In addition, for the PHQ9 measure, 38.6% of patients showed a clinically meaningful change of 5 or more points on their post-onabotulinumtoxinA treatment. Results from the other outcome measures showed a statistically significant improvement based on drops in scores of 2.8 points on the HIT6 (P = <.0001), 3.1 points on the PDI (P = .0002), and 0.4 points for Headache Pain Level (P = .0078). EQ-5D scores increased by 0.03, which was a statistically significant change (P = .0078).

Study authors concluded that there may be an association between onabotulinumtoxinA treatment and decreased depression scores, but the results do not prove that treatment alleviates depression.1

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