Patients with rheumatoid arthritis who have an increase in pain at a single site could be suffering from a stress fracture, especially if they have a history of steroid use, UK researchers report in the Annals of the Rheumatic Diseases.

As senior investigator Dr. Philip N. Platt told AMN Health, “pain in limbs of patients with rheumatoid arthritis is not always due to their joint disease directly. They are predisposed to getting stress fractures,” which may not always be recognized.

Platt and colleagues at Freeman Hospital in Newcastle upon Tyne, reviewed data on 24 stress fractures in 18 rheumatoid arthritis patients who were seen at a single center over nearly a decade. These 18 patients, all of whom were women, represented only 0.8% of the entire rheumatoid arthritis clinic population.

However, the investigators believe that the true prevalence of stress fractures in rheumatoid arthritis patients is likely to be higher. The design of this study and the difficulty in diagnosing stress fractures, they say, may lead to under-diagnosis.

Eleven of the 18 stress fracture patients were current oral corticosteroid users and 14 were past users.

When the team matched the 18 rheumatoid arthritis stress fracture patients with 18 rheumatoid arthritis patients without stress fractures, they found that steroid use was significantly more common in the stress fracture patients.

Bone mineral density measurement of the hip and spine, however, did not differ significantly between the two groups. This finding is in contrast to those of a number of previous studies that have suggested low bone mineral density may explain the risk of stress fractures in rheumatoid arthritis patients.

Nevertheless, the researchers urge health care providers who treat rheumatoid arthritis patients to be aware of the possibility of stress fracture in patients who develop an increase in pain at a single site.

SOURCE: Annals of the Rheumatic Diseases, December 2004.