A new study suggests that rheumatoid arthritis (RA) patients with fibromyalgia (FM) present significant 2-year worsening of functional status when compared to RA patients without FM. The abstract of the study, entitled “Fibromyalgia Predicts Two-Year Changes in Functional Status in Rheumatoid Arthritis Patients”, was presented during the 2015 ACR/ARHP Annual Meeting. The abstract is available online at the American College of Rheumatology Meeting Abstracts website.

Fibromyalgia is a debilitating and chronic condition associated with muscular or musculoskeletal pain, fatigue, mobility issues, with symptoms varying from patient to patient. According to the American Fibromyalgia Syndrome Association Inc, 3 to 5% of the general population is affected by this condition. Specifically, people suffering from other rheumatoid diseases such as lupus or rheumatoid arthritis, are at an increased risk of developing the condition. According to the Arthritis Foundation, about 20 to 30% of people with RA will also develop fibromyalgia, though the causes for this association are still unknown.

Previous studies have shown that RA patients affected by FM experience worse quality of life and increased disease activity and medical costs than RA patients that do not develop FM. In this study, researchers aimed to evaluate the impact of FM in RA patients’ lives on 2-year changes in functional status. A total of 156 RA patients were enrolled in the study, of which 26 had FM and 130 did not. Patients completed questionnaires every six months along with yearly laboratory tests and physical evaluation. Functional analysis was determined by two surveys: the Multidimensional Health Assessment Questionnaire (MDHAQ), which scores on a scale of 0-3 (3 indicating the worst status), and the FM survey scale, which predicts FM status and is made of two scales measuring widespread body pain and somatic symptoms.

Survey results were associated through mathematical models and adjusted patients’ personal and medical characteristics, showing that RA patients with FM had significantly higher baseline MDHAQ scores and Hospital Anxiety and Depression Scale scores. This increase was 0.15 units higher in RA patients suffering from FM. Moreover, higher FM survey scores were significantly associated with higher 2-year increases in the MDHAQ score.

Researchers concluded that the observed difference was striking given that “MDHAQ scores typically only increase 0.01-0.016 units per year in stable RA patients. Future studies are needed to determine if treatments for FM can reduce functional status decline among individuals with established RA.”