Study Finds Association Between Migraine, Fibromyalgia Onset

Using nationwide data, researchers recently found a 2-way association between onset of fibromyalgia (FM) and that of migraine in patients with migraine and those with FM, respectively.

Migraine and FM are common chronic pain disorders that tend to coexist, and a major symptom of FM is headache. Previous studies have reported that about 20% to 36% of patients with migraine also have FM. Similarly, the frequency of migraine in patients with FM ranges from 45% to 80%, suggesting that migraine is common in patients with FM. However, no explanations have been provided for the rate of co-occurrence.

This study examined whether these 2 conditions show any mutual influences and considered the conditions in the same context. This retrospective, longitudinal cohort study was conducted using data obtained from a nationwide healthcare database. This study, consisting of patients who were diagnosed between 2000 and 2010, had 2 arms:

• Arm 1 comprised 33,216 patients with FM
• Arm 2 consisted of 7420 patients with migraine

Control subjects who had neither FM nor migraine were recruited and matched with the FM and migraine patients by sex, age, and index date of diagnosis. Each control cohort was 4 times the size of the corresponding study cohort. Follow-up for the control and study cohorts was conducted until the end of 2011.

The incidence rates of FM and migraine were calculated in arms 1 and 2, respectively. The overall incidence of migraine was greater in the FM cohort than in the corresponding control cohort (4.39 vs 2.07 per 1000 person-years [PY]; crude hazard ratio [HR], 2.12; 95% CI, 1.96-2.30; adjusted hazard ratio (aHR), 1.89; 95% CI, 1.75-2.05).

After adjustment for sex, age, and comorbidities, the overall incidence of FM in the migraine cohort was 1.57 times greater than that in the corresponding control cohort (7.01 vs 4.49 per 1000 PY; aHR, 1.52; 95% CI, 1.39-1.65).

The authors said this study was the first to reveal a population-based bidirectional association between onset of FM and that of migraine in patients with migraine and those with FM, respectively. The risk of migraine was reportedly greater than that of FM. The incidence rates of FM in the migraine cohort and migraine in the FM cohort increased with age in both directions. However, the HRs relative to the corresponding comparison groups were weakened with increases in age.

Reference

Penn I-W, Chuang E, Chuang T-Y, Lin CL, Kao CH. Bidirectional association between migraine and fibromyalgia: retrospective cohort analyses of two populations [published online April 8, 2019]. BMJ Open. doi: 10.1136/bmjopen-2018-026581.