The Global Assessment of Migraine Severity (GAMS) is a valid tool to measure the severity of patient-reported migraine and may be a brief and efficient way to identify clinical and psychological determinants and mediators of patient-reported severity of migraine, according to a study published in BMC Neurology.
Researchers hypothesized that patients’ ratings of migraine severity would be strongly correlated with other validated measures of migraine severity and patients’ psychosocial characteristics. They recruited a cohort of 263 adult patients with migraine consecutively enrolled in the Neurological Disease and Depression Study in Calgary, Canada between 2012 and January 2013.
Patients enrolled were at least 18 years old, and spoke and read English. They also had no hearing impairment, diagnosis of dementia, development delay, or aphasia.
The investigators obtained a broad range of clinical (migraine frequency, subtype, number of years since migraine onset, the effect from medication) and patient-reported measures (patients’ ratings of migraine severity using GAMS and migraine-related disability, as measured by the Migraine Disability Scale [MIDAS]). Depression was measured using the 9-item Patient Health Questionnaire and the 14-item Hospital Anxiety and Depression Scale. Median regression analysis was used to examine the predictors of patient ratings of migraine severity.
Of the 263 participants, 209 (79.4%) were women, 66.5% were married or in a common-law relationship, and the mean age was 42.5 years (SD=13.2). Of these, 177 (67.4%) participants reported “moderately severe” to “extremely severe” migraine on the GAMS, and 100 (31.6%) patients had chronic migraine.
Patients’ report of severity on the GAMS was strongly correlated with patients’ ratings of MIDAS global severity question, overall MIDAS score, migraine type, 9-item Patient Health Questionnaire score, and frequency of migraine attacks.
Mediation analyses revealed that MIDAS mediated the effect of depression on patient ratings of migraine severity, accounting for about 32% of the total effect of depression. Overall, migraine subtype, the frequency of migraine, employment status, depression, and migraine-related disability were statistically significant predictors of patient-ratings of migraine severity.
The limitations of the study included the lack of assessment of the reliability of GAMS due to the cross-sectional nature of the study design. Some of the included participants may have had concomitant medication overuse headache. Across subgroups, there might have been variations in the degree of migraine severity, which could have limited the generalizability of the study.
Researchers of the study concluded that GAMS can be used to obtain a global statement directly from patients about their perception of migraine severity, which makes it an ideal tool to assess the severity of migraine in busy clinical settings.
Sajobi TT, Amoozegar F, Wang M, et al. Global assessment of migraine severity measure: preliminary evidence of construct validity. BMC Neurol. 2019;19(1):53.