Objective Assessment of Disease Activity and Remission in Rheumatoid Arthritis

Abstract

Rheumatoid arthritis (RA) is a common autoimmune disease leading to severe disability and premature mortality with incidence ranging from 5 to 50 per 100 000 adults in developed countries. Accurate assessment of disease activity and joint damage in RA is important for monitoring treatment efficiency and for prediction of the outcome of the disease. Management of RA and the determination of treatment decisions depend largely on the level of disease activity. There is no single gold standard for quantifying the level of disease activity. In clinical practice, a number of parameters (such as clinical assessment of tender and swollen joints, a global assessment of disease activity, and either an ESR or CRP level) are used to determine the level of RA disease activity. A number of validated instruments for RA in the form of composite indices that combine these parameters into a score are used in clinical practice, including disease activity score (DAS28), simplified disease activity index (SDAI) and ACR remission criteria. They allowed us to quantify the level of disease activity at any given point in time. Within the last decade, musculoskeletal ultrasonography has played an increasingly important role in the evaluation and monitoring of patients with chronic inflammatory arthritis. US can readily evaluate synovitis, a pathological hallmark of RA at both the anatomic and vascular levels. It also can detect the presence of bony erosion which is a cardinal finding in RA joints as a result of pathological destructive changes. Power Doppler US has the ability to identify the presence of vascularization that is associated with the presence of inflammation. MRI has undoubtedly enhanced the understanding of the pathophysiology of inflammatory changes in RA. It allows a three- dimensional precise assessment of the bony and surrounding soft tissue structures within a targeted joint. The main ‘activity’ findings detected by MRI include synovitis, tenosynovitis and BME while the ‘damage’ findings include bony erosions and JSN. MRI also avoids ionizing radiation and the images obtained can be stored and read centrally, which is useful for multi-centre clinical trials. The aim of this work was to evaluate patients with rheumatoid arthritis in activity and remission; clinically using DAS 28 score with other activity scores and objectively using high resolution ultrasonography, power Doppler ultrasono-graphy and magnetic resonance imaging, to document clinical findings and to identify the most sensitive objective method to be used in assessing activity and remission for patients follow up. This study was conducted on 50 RA patients and 10 healthy controls, the patients were recruited from the Physical medicine, Rehabilitation and Rheumatology out-patient clinic of Ain Shams University hospitals. All candidates underwent history talking and relevant clinical, laboratory and radiological testing to confirm or exclude the diagnosis and identify the degree of disease activity and extent of joints affection. All candidates underwent full medical history taking and thorough clinical examination with special emphasis on articular examination and laboratory investigation. All patients underwent assessment of degree of disease activity using modified DAS28 score, modified ACR criteria for remission and simplified disease activity index (SDAI). Patients were divided according to their DAS28 activity score into four groups, remission, low disease activity, moderate disease activity and high disease activity. Functional assessment of the patients was done using modified health assessment questionnaire and assessment of hand functions using Duruoz’s hand index.