Fibromyalgia is one of the most common causes of chronic pain and disability, characterized by widespread musculoskeletal pain accompanied by sleep problems, fatigue, and often emotional and mental distress. Fibromyalgia affects about 4 million US adults, or about 2% of the adult population. Despite extensive research the exact cause of fibromyalgia remains unknown, and there are no specific diagnostics or therapies for the condition other than prescribing pain-reducing drugs.
The discovery could dramatically alter the way chronic pain is identified, and revolutionize how fibromyalgia and related forms of chronic pain are treated, including reducing the use of opiates for pain management.
The researchers were able to identify patients with fibromyalgia using a common blood test for insulin resistance, or pre-diabetes. They then treated the patients with metformin, a medication used to treat insulin resistance, to dramatically reduce patient pain levels.
“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,” Pappolla said. “We showed that most – if not all – patients with fibromyalgia can be identified by their A1c levels, which reflects average blood sugar levels over the past two to three months.”
Pre-diabetics with slightly elevated A1c values carry a higher risk of developing central (brain) pain, a hallmark of fibromyalgia and other chronic pain disorders.”
The researchers identified patients who were referred to a subspecialty pain medicine clinic to be treated for widespread muscular/connective tissue pain. All patients who met the criteria for fibromyalgia were separated into smaller groups by age. When compared with age-matched controls, the A1c levels of the fibromyalgia patients were significantly higher.
“Considering the extensive research on fibromyalgia, we were puzzled that prior studies had overlooked this simple connection,” said Pappolla. “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.”
Source: Miguel A. Pappolla, Laxmaiah Manchikanti, Clark R. Andersen, Nigel H. Greig, et.al. Is insulin resistance the cause of fibromyalgia? A preliminary report. PLOS ONE, 2019; 14 (5): e0216079 DOI: 10.1371/journal.pone.0216079