Based on the modified 2010 American College of Rheumatology criteria, the prevalence of fibromyalgia is relatively high among chronic pain patients referred to outpatient pain clinics in Korea, an epidemiological study reports.
Consequently, pain physicians should keep in mind the prevalence of this condition when diagnosing these patients, researchers suggest.
The study, “Prevalence of fibromyalgia in fourteen Korean tertiary care university hospital pain clinics,” was published in the Journal of Pain Research.
Fibromyalgia is characterized by widespread muscle pain, fatigue, sleep disturbance, and memory and mood issues. Chronic pain, one of the hallmarks of the condition, is caused by alterations in the brain and the central nervous system, which causes the body to overreact to pain and other external stimuli, such as noise, smell, and bright lights.
In 1990, the American College of Rheumatology (ACR) defined the first diagnostic criteria for fibromyalgia, but this set of guidelines was considered by many as highly subjective, time-consuming, and noninclusive. In an attempt to improve this system, the ACR released new diagnostic criteria in 2010 specifically designed to facilitate their application in clinical practice.
“In these revised 2010 criteria, a widespread pain index (WPI), a specific type of self-report scale, was included in place of the previous tender point diagnostic criteria. A symptom severity (SS) scale was also proposed, with a focus on the comorbid symptoms experienced by FM [fibromyalgia] patients,” the investigators wrote.
Despite the improvements, the 2010 ACR criteria still required the presence of a certified physician to assess the presence and severity of patients’ symptoms. In 2011, the ACR criteria were modified again to remove this prerequisite. It was replaced with a summary score representative of three self-reported symptoms to make the implementation of the new diagnostic criteria more affordable and straightforward.
In this epidemiological study, investigators set out to analyze the incidence of fibromyalgia in a group of chronic pain patients who regularly visited pain clinics in Korea using the modified 2010 ACR criteria, as well as the prevalence of coexisting conditions, or comorbidities, related to fibromyalgia.
The multicenter, cross-sectional study enrolled 1,233 chronic pain patients — 754 men and 479 women — who visited pain clinics at any of 14 tertiary care university hospitals in Korea.
Patient diagnosis was determined based on the modified 2010 ACR criteria. Additional demographic information and comorbidities, including sleep disturbance, fatigue, irritable bowel syndrome, amnesia, hypothyroidism, headaches, anxiety, depression, rheumatism, low back pain, and history of traffic accidents, were assessed through questionnaires.
According to the modified 2010 ACR criteria, 13.38% of the patients had fibromyalgia. After excluding those who had a medical history of fibromyalgia, the condition’s prevalence only dropped to 11%.
Data also revealed that patients diagnosed with fibromyalgia were more likely to have one or more comorbidities. Further regression analyses showed that female patients with a medical history of fibromyalgia and sleep disturbances, headaches, or a history of traffic accidents were more likely to have fibromyalgia.
“Because FM [fibromyalgia] is difficult to diagnose in the absence of clinical suspicion, pain physicians should consider the elevated prevalence of FM in patients who visit their clinics [to hasten patients’ diagnosis and treatment],” the authors wrote.
“Despite some limitations, the present study provides a meaningful contribution to the literature as the first multicenter epidemiological study [based on the modified 2010 ACR criteria] of FM in Korea. The results of this study are expected to be utilized in future epidemiological research on FM in Korea,” they added.