Clinical and sonographic enthesitis in psoriatic arthritis patients and its relation to serum calprotectin level

Investigate the clinical and sonographic characteristics of enthesitis in psoriatic arthritis (PsA) patients and its relation to psoriatic disease activity and serum calprotectin (CLP).

This cross-sectional study enrolled PsA patients, diagnosed according to the classification criteria for psoriatic arthritis and an equal number of age and sex matched healthy controls. In PsA patients, enthesitis was assessed clinically using Spondylarthritis Research Consortium of Canada (SPARCC) and sonographically using the Madrid Sonographic Enthesitis Index (MASEI). Serum CLP was measured in both groups.

Most of the enrolled 45 PsA patient, were diagnosed with clinical enthesitis at least at one entheseal site (n = 43, 95.6%). However, on sonographic assessment, only 51.1% (n = 23) of the patients studied were classified with entheseal disease, MASEI ≥ 18. Achilles tendon was the most frequently involved entheseal site on clinical and ultrasonographic assessment. Total MASEI positively correlated with Disease Activity in Psoriatic Arthritis (DAPSA) (p = 0.047). Serum CLP was significantly higher in PsA patients (38.76 ng/mL) compared to healthy controls (31.07 ng/mL, p = 0.01). Serum CLP positively correlated with SPARCC, total MASEI and DAPSA (p = 0.002, 0.001 and 0.003, respectively). Serum CLP and MASEI were significantly lower in PsA patients on biological treatment compared to those on conventional treatment (p < 0.001).

PsA patients with entheseal disease might have higher disease activity. Serum CLP showed potential association with disease activity and entheseal involvement in PsA patients.