RMD Open
(mg/dL). The Clinical Disease Activity Index (CDAI) employs the same four clinical variables but omits CRP. The SDAI and CDAI scoring systems incorporate a multidimensional compensation framework where elevated joint counts (up to three swollen or tender joints in SDAI remission ( ≤ 3.3) and two swollen or tender joints in CDAI remission ( ≤ 2.8)) may be offset by improvements in patient-reported outcomes (PROs) and normalised acute-phase reactants, resulting in maintained classification within the remission range. 5 6 Boolean remission criteria defined by the American College of Rheumatology (ACR) and the European Alli- ance of Associations for Rheumatology (EULAR), while requiring stricter thresholds (serum CRP level ≤ 1 mg/dL and patient global assessment ≤ 2/10), tolerate residual synovitis with a maximum allowable count of 1 swollen joint out of SJC28 and 1 tender joint out of TJC28 for remission classification. 7 Eliminating the residual inflam- matory lesions to achieve ‘true’ clinical remission may lead to better long-term remission. Previously, we defined clinical deep remission (CliDR) as a state characterised by the absence of tender or swollen joints, alongside normal levels of CRP and erythrocyte sedimentation rate (ESR), indicating minimisation of residual inflammation. 8 9 In this study, we present the first real-world evidence that achieving CliDR predicts both sustained remission and future relapse and enables safer drug tapering in patients with RA.
to insufficient follow-up, defined as having fewer than two DAS28-CRP assessments per year during the post- remission follow-up period. Ultimately, 145 patients who achieved DAS28-CRP remission and satisfied the above inclusion criteria were analysed. Among these, 32 patients met the criteria for CliDR. A detailed flow of participant selection is shown in figure 1. Data collection Baseline was defined as the time of initial DAS28-CRP remission attainment. Demographic data of the patients at baseline were collected, including gender, age, disease duration, smoking status and family history of RA. During the 5-year follow-up after remis- sion, longitudinal clinical variables were systematically recorded from patients’ medical records at each visit, encompassing TJC28, SJC28, extra-articular manifes- tations, comorbidities, key laboratory indicators such as CRP, ESR, rheumatoid factor (RF) and anti-CCP antibodies. Additionally, detailed medication records were obtained, including DMARDs, corticosteroids and treatment adjustments. All variables included in the analysis had no missing data. The final dataset was complete for all baseline covariates and outcomes, with no imputation performed. Outcome measure and definition CliDR is defined as having no tender or swollen joints based on 28 joints with normal CRP and ESR levels. The normal range for CRP is defined as below the upper limit of normal, that is, 0–10 mg/L. The reference range for ESR is 0–15mm/hour in men and 0–20mm/hour in women. Remission according to the DAS28-CRP is defined as a score of DAS28-CRP<2.6, and relapse was defined as an increase in DAS28-CRP of >0.6 from the baseline value and DAS28-CRP >2.6 at any scheduled follow-up visit. 10 Recur- rent event refers to each investigator-reported relapse after the initial remission; event density denotes the average number of relapses per patient-year of follow-up. Sustained remission was defined as DAS28-CRP<2.6 documented at every visit for a minimum of six consec- utive months without any interim increase ≥ 0.6 units or escalation of DMARD therapy. Here, we compare the capacity of CliDR versus DAS28-CRP remission criteria to predict both sustained remission and subsequent relapse in patients with RA. Drug tapering was defined as dose reduction/discontinuation occurring at any point during follow-up. Statistical analysis All analyses were conducted using SPSS Statistics V.25.0. Categorical variables are expressed as frequencies (percentages), whereas continuous variables are presented as mean±SD. Between-group comparisons were conducted using the following methods: for continuous variables, the independent Student’s t-test was applied for normally distributed data and the Mann-Whitney U test was used
METHODS Patients
The observational cohort included a total of 541 patients with RA from the department of rheumatology and immunology at Peking University People’s Hospital. The enrolled patients were predominantly anti-cyclic citrul- linated peptide (anti-CCP) antibody positive and were treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs). The patients enrolled from January 2012 to December 2012, and the follow-up is ongoing. For this study, data up to January 2024 were analysed. Patients included in the analysis must meet the following inclusion criteria: (1) achievement of Disease Activity Score in 28 joints using C reactive protein (DAS28-CRP) remission at any visit; (2) a minimum of 5 years of continuous follow-up after the onset of remis- sion; (3) at least two DAS28-CRP assessments per year during this post-remission follow-up period. All patients met the 1987 ACR classification criteria. To ensure a uniform 5-year post-remission follow-up period for analysis, we established a data lock-in point of December 2018. First, patients lost to follow-up prior to this date (n=49) were excluded due to insufficient data. Furthermore, patients who had not achieved clin- ical remission by this cut-off (n=339) were excluded, as they could not provide information on sustained remis- sion over the 5-year period of interest. Additionally, eight patients who attained remission were excluded due
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Li H, et al . RMD Open 2026; 12 :e006387. doi:10.1136/rmdopen-2025-006387
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