Insulin Resistance May be Linked to Fibromyalgia, Preliminary Study Says

Insulin Resistance May be Linked to Fibromyalgia, Preliminary Study Says

Insulin resistance may be linked to fibromyalgia, which, if confirmed, could change the way physicians and patients face the disease, researchers say.

The preliminary study, “Is insulin resistance the cause of fibromyalgia? A preliminary report,” was published in PLOS One.

Fibromyalgia is a complex condition characterized by widespread muscle pain, fatigue, sleep disturbance, and memory and mood issues. Although the specific causes underlying the development of fibromyalgia are not clear, scientists think the condition arises from a disturbance of the nervous system that changes the way the brain interprets sensations, especially painful stimuli.

Insulin resistance (IR) is a condition in which the body’s cells become insensitive to insulin, a hormone produced by the spleen. This is the major cause of type 2 diabetes.

“Earlier studies discovered that insulin resistance causes dysfunction within the brain’s small blood vessels. Since this issue is also present in fibromyalgia, we investigated whether insulin resistance is the missing link in this disorder,” Miguel Pappolla, MD, PhD, professor of neurology at the University of Texas Medical Branch (UTMB) at Galveston, said in a news release.

In the study, researchers from UTMB and collaborators carried out a retrospective chart review of 23 patients with fibromyalgia, focusing on potential laboratory abnormalities that would enable them to distinguish these patients from healthy individuals.

They found that only the test assessing levels of glycated hemoglobin A1c (HbA1c) — the fraction of hemoglobin that is bound to glucose, or sugar, in the blood — normally used to identify pre-diabetic patients showing signs of IR was able to clearly separate those with fibromyalgia from two independent populations of non-diabetic subjects.

“We showed that most — if not all — patients with fibromyalgia can be identified by their A1c levels, which reflect average blood sugar levels over the past two to three months,” Pappolla said.

In addition, a sub-group analysis of patients eligible to be considered pre-diabetic or diabetic (HbA1c levels were higher than 5.7%) and who had been treated with metformin (a medication that controls blood sugar levels) showed these patients had a remarkable improvement in their numerical pain rating scale (NPRS) median scores before and after treatment (8.0 vs 0.25).

“Considering the extensive research on fibromyalgia, we were puzzled that prior studies had overlooked this simple connection,” Pappolla said. “The main reason for this oversight is that about half of fibromyalgia patients have A1c values currently considered within the normal range. However, this is the first study to analyze these levels normalized for the person’s age, as optimal A1c levels do vary throughout life. Adjustment for the patients’ age was critical in highlighting the differences between patients and control subjects.”

According to researchers, if these preliminary findings hold true in future studies, there will be a radical change in the way fibromyalgia and other chronic pain conditions are treated.

“If confirmed, our findings may translate not only into a radical paradigm shift for the management of FM but may also save billions of dollars to healthcare systems around the world,” they concluded.