Value of Entheseal Ultrasonography and Serum Cartilage Oligomeric Matrix Protein in the Preclinical Diagnosis of Psoriatic Arthritis

OBJECTIVE To evaluate the utility of entheseal ultrasonography and serum COMP in the preclinical diagnosis of psoriatic arthritis. METHODS 60 psoriatic patients were divided into: 30 patients with psoriasis (group I) and 30 patients with psoriatic arthritis as control (group II). They underwent independent clinical and ultrasonographic examination of both lower limbs at the calcaneal insertions of Achilles tendons. Psoriatic arthritis disease activity and severity was assessed by modified DAS28 and Steinbrockers scores. Serum levels of COMP were measured for all patients by ELISA. RESULTS On clinical examination, no entheseal abnormalities were detected in group I while they were present in 23.3% of group II with statistically significant difference between them (P < 0.001). Ultrasonographic entheseal abnormalities were detected in 33.3% of group I and in 46.7% of group II with no significant difference between them (P > 0.05). Serum COMP were significantly elevated in group I and II with no statistically significant difference between them (mean ± SD 5.9 ± 3 and 6.8 ± 12 respectively, P > 0.05). Entheseal ultrasound was more specific (67%) while serum COMP was more sensitive (87%) in the preclinical diagnosis of psoriatic arthritis. Serum COMP levels were significantly correlated with CRP in both groups and with DAS28 and Steinbrockers scores in group II (P < 0.01). CONCLUSION Entheseal ultrasonography and serum COMP levels may be used complementary to each other for preclinical diagnosis of psoriatic arthritis. Serum COMP seems to be promising prognostic marker for psoriatic arthritis patients.