Baseline calprotectin serum levels predicted disease relapse in patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA) undergoing therapy with tumor necrosis factor inhibitors (TNFi),  according to study results published in Arthritis Research & Therapy.

The results indicated that although time-to-remission/low disease activity, calprotectin serum levels, TNFi trough serum levels, and power Doppler scores were all significantly associated with disease relapse, only baseline calprotectin serum levels could independently predict disease relapse.

The study included participants with RA (n=47) and PsA (n=56) receiving TNFi who were in remission or had low disease activity (28-joint Disease Activity Score ≤3.2). The researchers used receiver operating characteristic analyses to assess the predictive value of calprotectin, TNFi trough serum levels, and power Doppler. They used Cox regression models to determine associations between baseline factors and relapse.

In total, 95 participants completed 1 year of follow-up. Of these, 12 participants experienced a relapse. At baseline, these participants had higher calprotectin levels, lower TNFi trough serum levels, and higher power Doppler activity compared with patients who did not experience relapse.

After performing receiver operating characteristic analysis, the researchers found that calprotectin fully predicted relapse (area under the curve [AUC], 1.00). They found that TNFi trough serum levels had an AUC of 0.790, and power Doppler had an AUC of 0.877.

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In multivariate analysis, the results indicated that only baseline calprotectin levels independently predicted disease relapse (HR, 2.41; P =.002).

“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,” the researchers wrote.

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Reference

Inciarte-Mundo J, Ramirez J, Hernandez MV, et al. Calprotectin strongly and independently predicts relapse in rheumatoid arthritis and polyarticular psoriatic arthritis patients treated with tumor necrosis factor inhibitors: a 1-year prospective cohort study [published online December 13, 2018].  Arthritis Res Ther. doi:10.1186/s13075-018-1764-z