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Background: Rheumatoid Arthritis (RA), a chronic autoimmune disease primarily affecting the synovial lining is characterised by flares alternating with remissions with subsequent accrual of joint damage that progresses into functional disability with considerable morbidity and mortality. Currently treatment with Disease Modifying Anti Rheumatic Drugs (DMARDs) has been demonstrated to retard the progression of disease and improve clinical outcomes. The Disease Activity Score for 28 joints (DAS28) score is one of the commonly used disease activity measures that combines clinical and serological data to evaluate the disease severity status of a patient. Musculoskeletal ultrasound (MSUS) with its greater anatomic resolution for soft tissues via high frequency transducers, coupled with Doppler imaging can provide a better insight into the amount of inflammation within a particular joint. Tenosynovitis, synovitis even erosions can be delineated in detail by musculoskeletal ultrasound, and can also be quantified by scoring systems. This makes musculoskeletal ultrasound sensitive to change in the disease status of the patient over a period of time and thus enable clinicians to gauge the efficacy of a particular treatment regimen.
Objective: The purpose of this study was to investigate the efficacy of musculoskeletal ultrasound (which includes greyscale plus Doppler ultrasound) in assessing the change in disease activity of rheumatoid arthritis patients within the wrist and hand joints, from the initiation of therapy to 3 months after, by comparing it to the DAS28 scores calculated during these times.
Design: This was a prospective analytical correlative study.
Setting: Patients were recruited from the Kenyatta National Hospital rheumatology outpatient clinic and were examined in the ultrasound room at the Department of Diagnostic Imaging and Radiation Medicine, University of Nairobi. The study was carried out over a period of 6 months from October 2019 to March 2020 including the initial musculoskeletal ultrasound scan followed up after a period of 3 months by a repeat exam.
Methods: The study involved patients diagnosed with rheumatoid arthritis, either newly initiated on treatment or subject to a change of regimen. These patients were evaluated at baseline and again after 3 months using the DAS28 structured questionnaire and musculoskeletal ultrasound parameters. The hand most affected by disease was examined and a total of 9 joints as well as extensor and flexor tendons of the wrist and hand were evaluated via ultrasound. MSUS parameters scored included greyscale synovitis, Doppler synovitis, Doppler tenosynovitis/ paratenonitis each scored for severity from 0-3, as well as erosions and tenosynovitis/paratenonitis which were scored for presence from 0-1. The means of all the scores were calculated for each interval period and statistically significant difference calculated. A comparison was made between the DAS 28 scores and musculoskeletal ultrasound parameters and the strength and direction of association assessed. Data was analysed using Scientific Package for Social Sciences (SPSS) version 22.0.
Results: The study found that there were statistically significant differences between the scores of DAS28 as well as MSUS parameters over the interval period with the exception of greyscale tenosynovitis/paratenonitis. A significant and positive association between DAS 28 and MSUS parameters was elicited with the exception of erosions. A strong association was measured between greyscale synovitis and DAS28 (r=0.818) with a moderate association established between Doppler synovitis (r=0.422), greyscale and Doppler tenosynovitis/ paratenonitis (r=0.38), (r=0.339) respectively and DAS 28 scores.
Conclusion: This shows that MSUS is a reliable and accurate tool for the measurement and follow up of disease activity within the wrist and hands of rheumatoid arthritis patients over a period of time.