The prevalence and clinical features of fibromyalgia in Chinese hospital patients with primary headache: The survey of fibromyalgia comorbid with headache.

Objective: The aims were to explore the prevalence and clinical features of fibromyalgia in Chinese hospital patients with primary headache.

Background: Studies done in non-Chinese populations suggest that around one-third of patients with primary headache have fibromyalgia, but data from mainland China are limited. Investigations into the prevalence and clinical features of fibromyalgia in Chinese patients with primary headache would improve our understanding of these two complex disease areas and help guide future clinical practice.

Methods: This cross-sectional study included adults with primary headache treated at 23 Chinese hospitals from September 2020 to May 2021. Fibromyalgia was diagnosed using the modified 2010 American College of Rheumatology criteria. Mood and insomnia were evaluated employing the Hospital Anxiety and Depression Scale and the Insomnia Severity Index.

Results: A total of 2782 participants were analyzed. The fibromyalgia prevalence was 6.0% (166/2782; 95% confidence interval: 5.1%, 6.8%). Compared to primary headache patients without combined fibromyalgia, patients with primary headache combined with fibromyalgia were more likely to be older (47.8 vs. 41.7 years), women (83.7% [139/166] vs. 72.8% [1904/2616]), less educated (65.1% [108/166] vs. 45.2% [1183/2616]), and with longer-duration headache (10.0 vs. 8.0 years). Such patients were more likely to exhibit comorbid depression (34.3% [57/166] vs. 9.9% [260/2616]), anxiety (16.3% [27/166] vs. 2.7% [70/2612]), and insomnia (58.4% [97/166] vs. 17.1% [447/2616]). Fibromyalgia was more prevalent in those with chronic (rather than episodic) migraine (11.1% [46/414] vs. 4.4% [72/1653], p < 0.001) and chronic (rather than episodic) tension-type headache (11.5% [27/235] vs. 4.6% [19/409], p = 0.001). Most fibromyalgia pain was in the shoulders, neck, and upper back.

Conclusions: The prevalence of fibromyalgia in mainland Chinese patients with primary headache was 6.0%. Fibromyalgia was more common in those with chronic rather than episodic headache. The most common sites of fibromyalgia pain were the neck, shoulders, and back.