23 May 2019

Could insulin resistance cause fibromyalgia?

Conditions Fibromyalgia

Metformin, the insulin-resistance wonder drug might have a role in rheumatology with new research suggesting it could as much as halve the severity of fibromyalgia pain.

In a small study, published in PLOS One, researchers found that patients with fibromyalgia had HbA1c levels that were higher that unaffected individuals matched for common variables.

To investigate whether lowering the blood sugar could affect the fibromyalgia symptoms, patients treated with metformin and had their pain levels monitored by means of a self-reported numeric pain rating scale.

Over the following eight to 36 months, patients taking metformin reported significantly lower pain scores.

“Metformin may have an effect in chronic pain independent of its action on [insulin resistance],” the authors said.

Commenting on the findings, Professor Geoffrey Littlejohn, a rheumatologist and clinical professor at Monash University, said the possibility of a new agent providing pain relief would be welcomed for fibromyalgia patients.

“It’s interesting there might be a commonly available drug that’s cheap and known to everyone that could affect pain in this population that desperately needs new management strategies,” he said.

Despite being extensively researched, the cause of fibromyalgia remains unknown. There are no specific diagnostic tests and no definitively proven effective therapies.

Professor Littlejohn said the current study was certainly of interest, but the observed link between fibromyalgia and raised HbA1c did not necessarily prove that insulin resistance caused fibromyalgia.

“[The association] could be due to the fact these people have chronic pain and aren’t exercising very much. They may be a bit overweight; they might be under stress, they might be eating poorly – all factors which would cause the link between insulin resistance and fibromyalgia,” he said.

Nonetheless, Professor Littlejohn said he would start watching his fibromyalgia patients who were on metformin, and ask about pain, but it was too early to change treatment.

“I won’t be prescribing metformin just on the basis of this study,” he said.

PLOS One 2019, 6 May (online)