“Causation between acute whiplash injury and fibromyalgia should not be implied via the results of the current study,” wrote Robert Ferrari, MD, at the University of Alberta, Edmonton, Alberta.

He prospectively evaluated consecutive acute whiplash-injured patients who presented to primary care centers within 14 days of their collision. All 268 patients who were enrolled were referred to Dr. Ferrari, who was acting as a specialist consultant. Participants were asked at 3 months, 6 months, and 1 year if they believed that they had recovered from their injuries, and were also assessed for fibromyalgia using the 2010 Modified American College of Rheumatology (ACR) criteria near the follow-up periods. Their mean age was 38.5 years and 54% were female. Of the 268 initial participants, 264 had 1-year follow-up data.

At 3 months, 6 months, and 1 year, 62%, 76%, and 82%, respectively, reported recovery from injuries.

At 3 months, no patient met the Modified 2010 ACR criteria for fibromyalgia. Three met these criteria at 6 months but had diagnoses other than fibromyalgia to explain their pain (polymyalgia rheumatica, ankylosing spondylitis, and polymyositis). Two met the criteria at 1 year with no other explanation for their symptoms.

“The results are not surprising, as 80% of the acute whiplash-injured participants had recovered at 1 year,” Dr. Ferrari wrote. “This leaves only 20% who could be at risk for fibromyalgia. When one examines the non-recovered participants, however, even though they have chronic pain and disability, they often report very localized pain disorders, such as chronic headache, chronic neck pain only, or even chronic low back pain only.”

One limitation of the study is that an examination by a rheumatologist was not performed in all 48 of the non-recovered participants at 1 year, meaning that some cases of fibromyalgia may have been missed.