Calprotectin levels predict relapse risk in RA, PsA patients treated with TNF inhibitors
medwireNews: Levels of serum calprotectin are significantly associated with the risk of disease relapse among tumour necrosis factor (TNF) inhibitor-treated patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA), researchers report.
The study included 95 patients (46.3% with RA; 53.7% with PsA) who were either in remission (disease activity score at 28 joints based on erythrocyte sedimentation rate [DAS28-ESR] ≤2.6) or had low disease activity (DAS28-ESR ≤3.2) at two consecutive clinic visits at least 3 months apart. In all, 46.3% of patients were undergoing etanercept treatment, while 35.8% were taking adalimumab and 17.9% infliximab.
As reported in Arthritis Research & Therapy, 12 patients experienced disease relapse – defined as DAS28-ESR greater than 3.2 with an increase of more than 0.6 points from baseline – over 1 year of follow-up.
Raimon Sanmarti (University of Barcelona, Spain) and colleagues found that patients who relapsed had significantly higher calprotectin levels at baseline than those who did not, at 6.01 versus 1.44 µg/mL.
And at a cutoff of 3.7 µg/mL, baseline calprotectin levels correctly distinguished between individuals who did and did not relapse on 100% of occasions, and calprotectin was significantly associated with relapse risk on multivariate analysis, with an adjusted hazard ratio (HR) of 2.74.
These findings indicate that calprotectin has “a high accuracy” for predicting relapse in this patient group, say the investigators.
They also demonstrated that patients who experienced relapse had lower average TNF inhibitor trough serum levels at baseline (1.14 vs 2.70 µg/mL), as well as greater rates of corticosteroid use (41.7 vs 15.7%) and a higher median power Doppler global ultrasound score in the hand (17.5 vs 8.0) than those who did not relapse. However, these variables were not significantly associated with relapse risk on multivariate analysis.
Sanmarti and colleagues caution that their study was limited by small patient numbers and the “low percentage of relapsing patients”, but note that previous research carried out in patients with juvenile idiopathic arthritis also demonstrated an association between calprotectin levels and relapse risk.
“Calprotectin 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”, they conclude.
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