3 Out of 4 Patients with Fibromyalgia Have Comorbid Temporomandibular Disorders

Pankaew Yakkaphan, DDS

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Temporomandibular disorders (TMDs) frequently coexist with fibromyalgia and chronic widespread pain (CWP), particularly for those with painful myogenous TMDs, according to research published in Journal of Oral and Facial Pain and Headache.¹

Fibromyalgia, a chronic condition considered a subgroup of CWP, is characterized by widespread musculoskeletal pain. Concomitant TMD and fibromyalgia is often regarded as a pair of chronic overlapping pain conditions (COPCs). Other COPCs include migraine, chronic tension-type headache, chronic lower back pain, chronic fatigue syndrome, and irritable bowel syndrome (IBS). The similarities between these conditions indicate they are related by epidemiology, symptomology, and underlying mechanisms.²

“Although several studies have considered the coexistence of fibromyalgia and TMDs, the association between these 2 disorders remains unexplicit,” wrote lead investigator Pankaew Yakkaphan, DDS, associated with the Faculty of Dentistry, Oral and Craniofacial Science, King's College London, United Kingdom, and colleagues. “Understanding the epidemiologic perspective of this association is instrumental to appropriately diagnosing and managing patients with these conditions.”

A systematic search was conducted among electronic databases, including PubMed, Scopus, Web of Science, MEDLINE, and PsycINFO, to determine the prevalence of CWP and fibromyalgia in patients with TMD, as well as the prevalence of TMDs in patients with fibromyalgia. Study quality was determined using the Newcastle-Ottawa Scale and pooled prevalence estimates were assessed using meta-analyses with defined diagnostic criteria.

A total of 19 moderate to high quality studies were included in the assessment, of which 9 evaluated the prevalence of CWP/fibromyalgia in patients with TMDs and 10 evaluated the prevalence of TMDs in patients with CWP/fibromyalgia. Most (n = 10) studies were case-control, 6 were cross-sectional, and 3 were cohort studies. Heterogeneity of the pooled studies was observed due to varying criteria guidelines and protocols, the subjectivity of patient and clinician assessment, and differences in application over time.

According to the meta-analyses, 3 out of 4 patients with fibromyalgia had concomitant TMDs (76.8% [69.5% - 83.3%]) and approximately one third (32.7%, 4.5% - 71.0%) of patients with TMDs had comorbid fibromyalgia. Compared with disc displacement disorders, myogenous TMDs were more prevalent in this patient population (63.1% [47.7% - 77.3%] vs 24.2% [19.4% - 39.5%], respectively). Comorbid inflammatory degenerative TMDs were observed in 41.8% (21.9% - 63.2%) of patients with fibromyalgia.

The highest proportions of patients with TMDs experiencing fibromyalgia symptoms were observed in a study of patients with painful disorders of the masticatory muscles lasting ≥6 months (63.2%), as well as a study in which patients were referred to a physiatrist to evaluate possible fibromyalgia (52.4%).

Estimates of comorbid CWP in patients with TMDs ranged from 30% to 76%, due in part to classification criteria variances.

As such, investigators noted the potential disparity in prevalence rates due to the differing diagnostic criteria as a limitation of their study. Additionally, although most patients (80% - 90%) were female, which is representative of fibromyalgia, results may not be generalizable to male patients with fibromyalgia and/or CWP. Further hindering generalizability, investigators mentioned most TMD samples were from patients with more severe TMDs who sought treatment. As TMDs are a collective condition, results may not reflect the larger patient population. Lastly, since the review was performed in 2020, there have been additional studies evaluating comorbid TMDs and fibromyalgia/CWP. However, newer findings reinforced the results from this analysis.

“These findings suggest a need for clinicians to consider the overlap between TMDs and CWP/fibromyalgia when treating affected populations, and, where appropriate, to consider multidisciplinary approaches to care,” investigators concluded.

References

1. ^{Yakkaphan P, Smith JG, Chana P, et al. Temporomandibular Disorders and Fibromyalgia Prevalence: A Systematic Review and Meta-Analysis. J Oral Facial Pain Headache. 2023;37(3):177-193. doi:10.11607/ofph.3260}
2. ^{Maixner W, Fillingim RB , Williams DA, Smith SB, Slade GD. Overlapping chronic pain conditions: Implications for diagnosis and classification. J Pain 2016;17(9 suppl):T93- T107.}