The effects of fibromyalgia in patients with rheumatoid arthritis

This study looked impact of fibromyalgia on physical function and pain in patients with rheumatoid arthritis. The authors concluded that patients with fibromyalgia or symptoms of fibromyalgia had worse functional ability than those without fibromyalgia.

Patients with rheumatoid arthritis (RA) can experience pain, swollen joints and a limited ability to carry out daily tasks (functional ability). Fibromyalgia occurs in approximately 20% of patients with RA compared to just 2% of the general population. Fibromyalgia is a condition where patients experience fatigue and widespread pain in their muscles. The combination of pain from swollen joints and pain as a result of fibromyalgia can lead to a reduced quality of life. Functional ability may be significantly reduced in patients affected by both RA and fibromyalgia. If fibromyalgia has a significant effect on functional ability, patients with both conditions may benefit from early treatment for fibromyalgia symptoms.

156 patients with RA were included in this study. The average age was 58.5 years. 16.7% of these patients were positive for fibromyalgia. Quality of life, functional ability, fibromyalgia symptoms, fatigue, RA disease activity, anxiety, and depression were all measured over a 2-year period.  

Patients with both RA and fibromyalgia had significantly lower functional ability at the beginning of the study than those with only RA. Over the 2 year follow-up, the average decrease in functional ability was 4 to 7 times higher for patients in both conditions compared to patients with RA only.

The decrease in levels of pain over 2 years was 2.95 greater in patients with fibromyalgia and RA than those with RA only. Increases in levels of anxiety were twice as high in patients with RA alone compared to those with RA and fibromyalgia.

The authors concluded that the presence of fibromyalgia or symptoms of fibromyalgia is associated with a decrease in functional ability in patients with RA. This was not affected by RA disease activity or psychological distress. 

The methods used in this study to define fibromyalgia have not been endorsed by the American College of Rheumatology.