Serum calprotectin predicts relapse risk in TNFi-treated RA, PsA
medwireNews: Serum calprotectin levels independently predict relapse risk in tumor necrosis factor (TNF) inhibitor-treated patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA) who are in remission or have low disease activity, Spanish researchers report.
Based on their findings, Raimon Sanmarti and colleagues from the University of Barcelona say that “[c]alprotectin may be used to stratify disease activity more accurately in patients with low disease activity, guiding therapeutic decisions towards safer and more cost-effective strategies.”
The study included 44 patients with RA and 51 with PsA who were either in remission (DAS28-ESR ≤2.6) or had low disease activity (DAS28-ESR ≤3.2) at two consecutive visits at least 3 months apart, and were receiving treatment with adalimumab, etanercept, or infliximab.
During 1 year of follow-up, eight (18%) patients with RA and four (8%) with PsA experienced disease relapse, defined as a DAS28 above 3.2 and an increase in DAS28 of more than 0.6 from baseline.
The patients who relapsed had significantly higher baseline calprotectin levels than those who did not (6.01 vs 1.44 μg/mL), and when the researchers used a cutoff of 3.7 μg/mL, receiver operating characteristic curve analysis showed that calprotectin levels predicted relapse with 100% accuracy.
Furthermore, calprotectin was the only significant independent predictor of relapse on multivariate analysis, with levels above 3.7 μg/mL associated with a 2.74-fold higher relapse risk than lower levels.
Sanmarti and team found no differences between relapsers and nonrelapsers in disease duration, biologic treatment duration, the proportion using a reduced dose of biologics, or the number using monotherapy.
By contrast, patients who relapsed had significantly lower baseline TNF inhibitor trough serum levels (1.14 vs 2.70 μg/mL) and a significantly higher power Doppler activity score (5.5 vs 1.0) than those who did not, but neither of these variables were significantly associated with relapse risk on multivariate analysis.
Writing in Arthritis Research & Therapy, Sanmarti et al say that the high accuracy of calprotectin level for predicting disease relapse “is not completely unexpected” because it has previously been shown to predict relapse in other inflammatory conditions, including juvenile idiopathic arthritis, systemic-onset juvenile idiopathic arthritis, antineutrophil cytoplasm antibody-associated vasculitis, and inflammatory bowel disease.
However, they caution that “[t]he small sample size and low percentage of relapsing patients (12.6%) could be a limitation” of their study.
By Laura Cowen
medwireNews is an independent medical news service provided by Springer Healthcare. © 2018 Springer Healthcare part of the Springer Nature group