Background Rheumatoid arthritis (RA) is a chronic systemic inflammatory disorder associated with progressive joint destruction. The rate of joint destruction is different among the patients. However, a few studies have been conducted to find out possible clinical predictors of radiographic damage in Asian populations compared with in Caucasians.
Objectives We aimed to identify potential clinical predictors of severe radiographic damage in Korean early RA patients.
Methods We studied 328 early RA patients with disease duration ≤2 years. Radiographic severity was assessed using the Sharp/Van der Heijde modified score (SHS) from hand radiographs, which were obtained at two time points separated by at least 1 year,. The yearly radiographic progression rate (ΔSHS/year) was calculated and the top 25% of the study population were defined as having severe radiographic damage, and the others as having mild radiographic damage. The covariates tested included age at symptom onset, Health Assessment Questionnaire score, smoking at symptom onset, body mass index, rheumatoid factor (RF), anti-CCP antibody, HLA-DRB1 shared epitope, Disease-modifying antirheumatic drug, baseline SHS, ESR, CRP and cumulative ESR and CRP during initial 6 months which were calculated using area under curve (AUC) of ESR (AUC-ESR) and ACU-CRP. Predictors of severe radiographic damage were tested using multivariate logistic regression models, adjusted for potential confounders. Given the strong correlations, the baseline ESR, CRP, AUC-ESR, and AUC-CRP were used as the covariates in different models.
Results Of the 328 patients with RA, 64% were female and the mean age at symptom onset was 48.9±12.0 years. The baseline SHS was 6.3±14.6 and it increased to 16.2±24.0 after a mean of 4.3±2.6 years. The ΔSHS/year cut-off for the top 25% was 4.1. Patients with severe radiographic change had higher percentage of RF (p=0.013), higher baseline SHS (p=0.002), and inflammatory markers (p=0.037, p=0.012, p=0.008, and p=0.014 for ESR, CRP, AUC-ESR, and AUC-CRP, respectively). In multivariate model, male (OR 2.620, 95% CI 1.117-6.147), RF (OR 2.464, 95% CI 1.093-5.558), baseline SHS (OR 1.936, 95% CI 1.423-2.634), ESR (OR 2.134, 95% CI 1.119–4.069), CRP (OR 2.622, 95% CI 1.430–4.805), and AUC-ESR (OR 2.487, 95% CI 1.328–4.659) were independent predictors of severe radiographic damage, but not AUC-CRP. In a subgroup analysis according to whether AUC-ESR decreased or increased compared with the baseline ESR, a higher baseline ESR was associated with severe radiographic damage only in the AUC-ESR increased subgroup (p=0.001). However, even though baseline ESR was high, if it decreased with time (AUC-ESR decreased subgroup), severe radiographic change was not developed (p=0.826)
Conclusions Male, RF, baseline SHS, baseline ESR and CRP were associated with severe radiographic damage in Korean patients with RA, which were consistent with findings of Caucasian studies except sex. In addition, the current study supports that strict control of disease activity during initial 6 month period which was represented by decrease of ESR is important to prevent radiographic damage, especially in higher baseline ESR subgroup.
Disclosure of Interest None declared