Abstract
Background
Several therapeutic options are currently available to treat rheumatoid arthritis (RA); however, the response to treatment is highly variable, and not all patients achieve clinical remission [1]. Obesity is suggested to lower the chances of remission [2], even though a recent observational study has shown that obesity is not associated with reduced response to conventional synthetic anti-rheumatic drugs in patients with early RA [3].
Objectives
The aim of this study is to determine if obesity affects the response to treatment in participants with early RA.
Methods
This report includes 393 Swedish patients from the NORD-STAR study, which is a multicenter, randomized trial on 812 patients with untreated early RA [4]. The 393 participants have been randomized at baseline into 4 arms of treatment: methotrexate combined with (1) prednisolone, (2) certolizumab, (3) abatacept, or (4) tocilizumab. Scores for disease activity and blood samples were measured and collected before randomization and at 24-week follow-up.
Multiple linear regression and binary logistic regression analyses were performed after adjustment for sex, baseline age, anti-citrullinated peptide antibody status, current smoking, disease activity score- C-reactive protein (DAS28-CRP), and treatment randomization. The outcomes for this report were: DAS28-CRP ≤3.2 (DAS28-CRP low disease activity), DAS28-CRP ≤2.6 (DAS28-CRP remission) and clinical disease activity index (CDAI) ≤2.8 (CDAI remission).
Results
In total, 75 (19%) participants had obesity at baseline, defined as body mass index (BMI) ≥30 kg/m2. The percentage of patients with obesity in each treatment group was (1) 25%, (2) 15%, (3) 19% and (4) 19%. At baseline, there were no differences in terms of disease activity indices and inflammation parameters between patients with BMI <30 vs. ≥30 kg/m2, except for the number of swollen joints (SJC28), which was slightly lower in those with obesity (mean+SD, 8±5 vs. 9±5, p=0.018). At 24-week follow-up, patients with obesity had higher disease activity indices and inflammation parameters compared to patients with lower BMI (Table 1). Moreover, patients with obesity had a lower chance of achieving response to treatment as measured by DAS28-CRP ≤3.2 (OR 0.5, 95% CI 0.2 - 0.9, p=0.025), DAS28-CRP ≤2.6 (OR 0.4, 95% CI 0.2 - 0.6, p <0.001) and CDAI remission (OR 0.4, 95% CI 0.2 - 0.8, p=0.006), compared to patients with lower BMI (Figure 1). BMI-treatment interaction was not significant for any score of disease activity.
Conclusion
In patients with early RA, obesity was not associated with higher disease activity before treatment initiation. However, 24 weeks after treatment, patients with obesity had higher disease activity and lower chances to respond to therapy compared to patients with lower BMI irrespective of treatment.
Several therapeutic options are currently available to treat rheumatoid arthritis (RA); however, the response to treatment is highly variable, and not all patients achieve clinical remission [1]. Obesity is suggested to lower the chances of remission [2], even though a recent observational study has shown that obesity is not associated with reduced response to conventional synthetic anti-rheumatic drugs in patients with early RA [3].
Objectives
The aim of this study is to determine if obesity affects the response to treatment in participants with early RA.
Methods
This report includes 393 Swedish patients from the NORD-STAR study, which is a multicenter, randomized trial on 812 patients with untreated early RA [4]. The 393 participants have been randomized at baseline into 4 arms of treatment: methotrexate combined with (1) prednisolone, (2) certolizumab, (3) abatacept, or (4) tocilizumab. Scores for disease activity and blood samples were measured and collected before randomization and at 24-week follow-up.
Multiple linear regression and binary logistic regression analyses were performed after adjustment for sex, baseline age, anti-citrullinated peptide antibody status, current smoking, disease activity score- C-reactive protein (DAS28-CRP), and treatment randomization. The outcomes for this report were: DAS28-CRP ≤3.2 (DAS28-CRP low disease activity), DAS28-CRP ≤2.6 (DAS28-CRP remission) and clinical disease activity index (CDAI) ≤2.8 (CDAI remission).
Results
In total, 75 (19%) participants had obesity at baseline, defined as body mass index (BMI) ≥30 kg/m2. The percentage of patients with obesity in each treatment group was (1) 25%, (2) 15%, (3) 19% and (4) 19%. At baseline, there were no differences in terms of disease activity indices and inflammation parameters between patients with BMI <30 vs. ≥30 kg/m2, except for the number of swollen joints (SJC28), which was slightly lower in those with obesity (mean+SD, 8±5 vs. 9±5, p=0.018). At 24-week follow-up, patients with obesity had higher disease activity indices and inflammation parameters compared to patients with lower BMI (Table 1). Moreover, patients with obesity had a lower chance of achieving response to treatment as measured by DAS28-CRP ≤3.2 (OR 0.5, 95% CI 0.2 - 0.9, p=0.025), DAS28-CRP ≤2.6 (OR 0.4, 95% CI 0.2 - 0.6, p <0.001) and CDAI remission (OR 0.4, 95% CI 0.2 - 0.8, p=0.006), compared to patients with lower BMI (Figure 1). BMI-treatment interaction was not significant for any score of disease activity.
Conclusion
In patients with early RA, obesity was not associated with higher disease activity before treatment initiation. However, 24 weeks after treatment, patients with obesity had higher disease activity and lower chances to respond to therapy compared to patients with lower BMI irrespective of treatment.
Original language | English |
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Journal | Annals of the Rheumatic Diseases |
Volume | 82 |
Issue number | Suppl 1 |
Pages (from-to) | 407-408 |
Number of pages | 2 |
ISSN | 0003-4967 |
DOIs | |
Publication status | Published - 2023 |