Comorbidity of migraine and fibromyalgia in patients with cluster headache: psychological burden and healthcare resource utilization. A cross-sectional study.

The aim was to describe the comorbidity and impact of fibromyalgia and/or migraine on patients with cluster headache. Comorbid diseases can exacerbate the physical and psychological burden experienced by patients. The comorbidities of cluster headache have been scarcely investigated, with the exception of migraine, which is well-known to coexist with cluster headache. In contrast, the comorbidity of migraine and fibromyalgia has been well investigated and firmly established. An internet survey was uploaded to the webpage of a cluster headache patient association. The survey collected sociodemographic and clinical data, and patients completed questionnaires that assessed depression, sleep quality, health-related quality of life, and health care resource utilization (HCRU) over the preceding six months. Differences in total depression, sleep quality, and health-related quality of life scores among the groups were analyzed with the Kruskal-Wallis test, and differences in HCRU were analyzed with the chi-square test. Ninety-one patients with cluster headache participated in the survey; 39 (42.9%) experienced only cluster headache, 15 (16.5%) experienced cluster headache and migraine, 10 (11%) experienced cluster headache and fibromyalgia, and 27 (29.7%) experienced cluster headache with comorbid fibromyalgia and migraine. Moderate depression scores and positive suicidal ideation were found across all subgroups. Sleep quality and health-related quality of life were consistently poor across the different subgroups, with the cluster headache with comorbid fibromyalgia and migraine subgroup showing significantly lower scores. Heavy use of health care resources was observed across all subgroups, with no notable differences among them. The comorbidity of cluster headache with fibromyalgia and/or migraine does not seem to be infrequent. This comorbidity substantially increases the psychosocial burden experienced by patients and decreases their overall quality of life.