Anxiety or Genes? New Study Adds Evidence to Search for What Causes Long-Term Pain in Patients Receiving Minor Surgeries

Research presented at this year’s American Society of Anesthesiologists Annual Meeting offers new data in the quest to develop tailor-made pain management strategies based upon a patient’s genetic predisposition and other important factors.

A study led by Craig T. Hartrick, M.D. and his team at the Anesthesiology Research Department, Beaumont Hospitals, Royal Oak, Michigan found that anxiety before surgery was associated with increased pain after three months, lower quality of life, increased reported feelings of pain sensitivity, and specific genetic configurations.

Chronic pain experienced well beyond the usual and expected period of healing is a common and frustrating problem for both surgical patients and the health care workers seeking ways to prevent such pain.

Dr. Hartrick followed 129 minimally invasive arthroscopic shoulder surgery patients to assess their pain status for three months after their procedures. Patients with a known genetic predisposition toward low sensitivity to pain were matched with patients with genetic predispositions toward high tolerance for pain and were controlled for sex, ethnicity, anxiety, duration of symptoms, age, and sensitivity and pain at the time of surgery.

Surprisingly, the low pain sensitivity patients were actually associated with high pain levels three months after surgery.

"While it was not unexpected that we found that anxiety at the time of surgery was associated with greater pain and disability after surgery, the low pain sensitivity patients would have been expected to be associated with a reduction in the incidence of persistent pain, not an increase," said Dr. Hartrick.

The study could not confirm whether the chronic pain experienced by the high-pain-tolerant patients was due to anxiety, a predisposition to the development of chronic pain, or other factors, but it does add strong evidence that future pain studies which fail to control for anxiety could risk misinterpreting their results, said Dr. Hartrick.

"Our findings highlight the importance of examining multiple factors when researching genetics and pain – especially those that may be inter-related or share common genetic features (anxiety, for example) – when designing outcome studies to predict the development of persistence pain conditions."