Correspondence on “relationship between the EULAR/ACR classification criteria and organ damage in systemic lupus erythematosus” by Chi Chiu Mok et al

We read with great interest the study by Chi Chiu Mok et al, on the relationship between the 2019 European League Against Rheumatism/American College of Rheumatology classification criteria (EULAR/ACR criteria) score and the development of organ damage in patients with Systemic Lupus Erythematosus. The authors showed that patients with a EULAR/ACR criteria score ≥20 on their last clinic visit had significantly higher Systemic Lupus International Collaborating Clinics (SLICC) Damage Index (SDI) scores compared to patients with a score < 20. They used the EULAR/ACR criteria score at the last visit to account for manifestations developing over time that could also contribute to the accrual of damage. The authors included a cross-sectional single-centered cohort of 562 patients who had a positive ANA (titer ≥1: 80) test and were diagnosed with clinical SLE by a panel of rheumatologists. Patients who fulfilled the EULAR/ ACR criteria (score ≥10) on their last clinic visit (542 patients) were divided into 2 groups; group 1, with a score of ≥20, and group 2, with a score of <20. Patients in group 1 had significantly higher total SDI scores and also scored higher in the renal, cardiovascular, gonadal and dermatological domains compared to group 2. Although, when they analyzed 251 patients that had a 10-year follow-up, no difference was found in the SDI scores at 10 years between patients with a score ≥20 versus < 20 in the first 2 visits. We have demonstrated that a EULAR/ACR criteria score ≥20 at diagnosis predicts a higher disease activity throughout the first 5 years after diagnosis. More recently we showed, consistent with the findings by Chi Chiu Mok et al, that a score ≥20 at diagnosis is able to predict long-term outcomes, including damage and mortality (3). Our study included 867 patients, patients with a score ≥20 more often accrued damage in the following 10 years (46% vs 40%, score ≥20 vs < 20, respectively, p = 0.02). Furthermore, the mean SDI at year 10 was significantly higher in the group with a score ≥20 (1.28 vs 0.97, score ≥20 vs < 20, respectively, p = 0.03) and when assessing the specific domains, this group also had more renal damage. These results were corroborated by multivariable regression analysis, patients with the higher score had a 40% increased risk of developing damage (HR 1.40, p = 0.002), and the risk persisted even when analyzing the subgroup of patients without lupus nephritis (HR 1.46, 0 = 0.006). In contrast to the results from Chi Chiu Mok et al, we found that the EULAR/ACR score at diagnosis was predictive for damage accrual in the following 10 years. Our study was powered by a higher number of participants which could explain this discrepancy in results (867 vs 251 participants in the analysis). The findings by Chi Chiu Mok et al and our group are also consistent with prior studies, further validating the concept that the EULAR/ACR criteria in addition to their classification capacity is also an indicator of ominosity, and could aid physicians to identify patients at risk for worse short and long-term outcomes.