Fibromyalgia (FM) and gastroesophageal reflux disease (GERD) appear to co-exist, an interrelationship that has has been documented.1.2 New research attempts to offer a clearer understanding of this co-morbidity after evaluating the medical records of more than 35,000 patients with both conditions and comparing them to thousands more without either condition.3
“The present study suggests a bidirectional relationship between FM and GERD,”3 the authors write in the October 2017 issue of Pain.
How Often Do GERD and Fibromyalgia Present?
Chia-Hung Kao, MD, professor of neurology at China Medical University in Taiwan, and colleagues examined the medical records of 35,117 patients with FM and 34,630 with GERD.3 All were newly diagnosed with both conditions between 2000 and 2010.
For each study arm, the researchers randomly selected four times the number of subjects with neither FM nor GERD from the same national database, the National Health Insurance of Taiwan.
The researchers calculated the incidence of GERD and FM in arms 1 and 2 by the end of 2011.3
- For GERD, the incidence was 1.6 times greater in the FM cohort than the non-FM group (crude HR 1.58, 95% CI.), with an adjusted HR of 1.27 (95% CI after controlling for sex, age, comorbidities, and medications.
- The incidence of FM was 1.5 times higher in the GERD cohort than the non-GERD cohort, with an adjusted HR of 1.44 (95% CI).
FM patients had a slighter greater risk of developing GERD than GERD patients did of getting FM. However, the researchers also found it took longer for a repeated reflux condition or steady heartburn to present in FM patients than for GERD patients to present with symptoms of FM.3
Offering an Explanation for an Apparent Association
While the researchers were not able to offer a clear explanation for the apparent interrelationship between GERD and FM, they pointed to depression as a possible precursor. There is some research to suggest that depression and anxiety were common in FM patients.4 It may be that they had a heightened sensitivity to small amounts of acid in the esophagus, or that the stress of trying to manage the chronic pain and other symptoms of FM may lead to a chronic reflux,3 according to the researchers.
The researchers also acknowledged that in patients with GERD, there may be many factors that play a role in an increased risk for FM, such as the use of NSAIDs.3 (Despite multiple attempts to reach the authors for comment, all requests went unanswered.)
“Untangling the link [between FM and GERD] is complicated,” said Don Goldenberg, MD, a fibromyalgia expert and affiliate faculty in rheumatology at Oregon Health & Science University in Portland, Maine, who reviewed the study findings.
Irritable bowel syndrome has an association with GERD, said Dr. Goldenberg, and IBS is common in FM patients.
“Fibromyalgia and irritable bowel syndrome are classical functional pain disorders,” Dr. Goldenberg told Practical Pain Management, and while not confirmed, GERD also appears to have an association with functional GI pain disorders.
The authors also pointed out that heartburn and regurgitation provoked unrefreshing sleep, and this interrelationship in which sleep deprivation exacerbates pain and increases the risk for fibromyalgia is also a noted factor in managing patients with FM, he said.
Fibromyalgia is a difficult condition to study, Dr. Goldenberg said, “Patients have a lot of symptoms, and, they see doctors so much, of course, so they are going to be diagnosed with more bothersome symptoms than patients with less systemic, non-chronic, pain conditions.”
Are the Findings Clinically Applicable?
“This study appears to offer a solid finding and a new finding,” said Dr. Goldenberg.
However, whether the findings ultimately will be helpful to clinicians remains to be seen, said Michael R. Clark, MD, MPH, MBA, director of the Pain Treatment Program at Johns Hopkins University in Baltimore, Maryland.
“Patients with chronic pain disorders like FM and IBS, headache, and such, have overlapping symptoms that are likely to have some common pathway,” Dr. Clark told Practical Pain Management. No one has yet to be able to confirm whether patients tend to be focused on bodily sensations and complain about symptoms of heartburn or whether they have a common pathophysiology like central sensitization or some other linked pathology as the researchers in this paper are suggesting, he said.
For now, the study should serve to raise awareness about the likelihood of an increased prevalence of co-morbidity.
“Clinicians should be more alert to the possibility of this association,” Dr. Goldenberg said. “For pain practitioners, routinely asking FM patients about any problems with irritable bowel and repeated reflux would be a very good start.