For people living with rheumatoid arthritis (RA), the level of disease activity—measured using the standard DAS 28 score—is the factor most strongly affecting the level of RA-related disability, according to a study in JCR: Journal of Clinical Rheumatology. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, and pharmacy.
Bone damage related to RA contributes to disability after the disease has been present for a few years, but still doesn't match the impact of disease activity, according to the study led by Dr E.E. Schneeberger of Instituto de Rehabilitación Psicofísica, Buenos Aires. The study also finds that treatment with disease-modifying antirheumatic drugs (DMARDs) to reduce disease activity is the only factor with a positive effect on the level of RA disability.
Disease Activity, Structural Damage and Morning Stiffness Affect RA Disability
Using a standard questionnaire, the researchers assessed functional ability in several key areas (for example, walking, bathing, and self-care) in 640 patients with RA. Eighty-five percent of the patients were women. The average age was 53 years, and RA had been present for an average of 8 years.
The DAS 28 score was used to assess the level of RA disease activity, based on factors like the number of tender, swollen joints, a laboratory test of inflammation, and the patient's general health. X-rays were used to evaluate RA damage to the bones of the hands and feet. These, along with other patient and medical characteristics, were analyzed to see which factors had the greatest impact on disability from RA.
Patients with a higher overall level of disease activity—as reflected by the DAS 28 score—had greater disability from RA. Disability was also increased for patients with more morning stiffness and in those who had had RA for a longer time. Increased bone damage on x-rays and older age were also linked to increased disability.
After adjustment for other factors, the DAS 28 score was the strongest predictor of disability. Bone damage became a significant contributor to disability for patients who had had RA for a longer time—more than two years. However, it never surpassed the impact of disease activity.
Although certain economic and social factors seemed to be related to increased disability, these were no longer significant after adjustment for disease activity and other factors. Performed in Argentina, the study is one of the first to look at factors affecting RA disability in a developing country.
Treatment with DMARDs Linked to Reduced Disability
Only one factor was related to lower disability from RA: treatment with DMARDs. These are medications, such as methotrexate, that actually slow the process of joint destruction. Other medications, such as steroids, can help to reduce inflammation in patients with RA, but do not alter the course of the disease.
Rheumatoid arthritis is a major cause of disability among younger adults, especially women. The disease most commonly starts when patients are in their prime working years—their forties and fifties. Several factors may affect the risk of disability from RA, such as symptoms, inflammation, and so forth. The new study was designed to evaluate the main causes of disability in patients with RA.
The results suggest that the level of disease activity—as measured by the widely used DAS 28 score—is the most important factor predicting the level of disability from RA. Although bone damage contributes to disability, especially as RA progresses, it never becomes more important than the overall level of disease activity. This suggests that treatment with DMARDs to control disease activity might help to lessen the disability caused by RA.
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