Can Early, Clinically Significant Radiographic Progression In The First Year Of Disease Predict Orthopaedic Surgery In Patients With Rheumatoid Arthritis?
BACKGROUND: Orthopaedic intervention is an important outcome in Rheumatoid Arthritis (RA). The use of radiographic data in the early stages of the disease and its importance in determining future RA related outcomes is relatively understudied. The Larsen and Sharpe/van der Heijde (SvdH) scoring methods are means of quantifying radiographic damage that take into account both erosions and joint space narrowing. Whether radiographic scoring is useful in predicting long-term (up to 25 years) orthopaedic risk is unknown. METHOD: The Early Rheumatoid Arthritis Study (ERAS) is an inception cohort that has collected data on 1,465 RA patients from set up in 1986 for up to 25 years. Data included demographics, disease activity (DAS), functional disability (HAQ) and radiographs of hands & feet (Larsen & SvdH). The Smallest Detectable Difference (SDD) for the Larsen and SvdH data was calculated to be 4 and 5 respectively, and therefore these will be used as the cut-points for the analysis. Orthopaedic interventions were classified as either intermediate for small joint surgery of hands and feet, and major for large joint replacement (mainly hips and knees). RESULTS: A total of 1,013 patients had Larsen scores at both baseline and 1-year. 206 patients had a change in Larsen of >=4 (20.34%). A sub-sample of 270 patients had SvdH scores for both baseline and 1-year. 189 had a SvdH score of >=5 (70%). A competing risk regression analysis was undertaken to investigate whether patients with significant progression of Larsen scores (change of >=4) and SvdH scores (>=5) from baseline to 1 year were more at risk of both intermediate and major orthopaedic intervention types. Controlling for age at onset, sex, recruitment year, baseline DAS, baseline HAQ and baseline Larsen/SvdH score, significant changes in Larsen scores from baseline to 1 year indicated a strong significant predictor of both intermediate (SHR 1.76; P<0.05) and major (SHR 1.92; P<0.05) orthopaedic interventions. A similar trend was seen in the SvdH scores for both Intermediate (SHR 2.58; P<0.05) and major interventions (SHR 2.74; P<0.05). DISCUSSION: Structural joint damage in the early stages of RA is common, and those patients that experience rapid progression in the first year of disease are at much higher risk of orthopaedic intervention of the hands or feet or large joints. What is interesting is the stronger effect seen for large joints, based on markers that primarily focus on the small joints of the hands and feet. This indicates that rapid progression in small joints may be intrinsically linked with subsequent damage in larger joints later on in the disease.