Biomarkers to Distinguish Psoriatic Arthritis Prove Elusive, Study Says

Rheumatologists who have been looking for serological markers to distinguish psoriatric arthritis (PsA) from psoriasis may have to continue their hunt, based on results appearing this week in Clinical Rheumatology.

Catching PsA early has been a challenge even when the diagnosis is aided by sonography, according to the authors. The difficulty shows up in the literature, such as a 2018 study that discussed the need to reclassifying patients with psoriasis as having PsA once their symptoms progressed. Yet finding and treating PsA early is essential to avoid disability.

“The under-diagnosis of PSA among persons with psoriasis not only delays treatment but also increases the risk of joint damage,” they wrote. “In one study, the rate of PSA under-diagnosis was estimated to be about 9%. Early diagnosis of PSA could also increase awareness in doctors to treat comorbidities.”

The authors retrospectively analyzed serological markers and comorbidities in 629 psoriatic patients, including 102 with PsA; the others had psoriasis. The serological markers were not useful (P > .05 for all comparisons). Prevalence of PsA among the psoriasis patients was 19.4%.

According to the study, the team found no early warning for PsA after testing for total leukocyte count, platelets, hemoglobin, hematocrit, lipoprotein profile, inflammation markers (C-reactive protein, erythrocyte sediment rate), titers of anti-nuclear antibodies, or rheumatoid factor.

Comorbidities proved more useful. Metabolic syndrome-hyperlipidemia (2.94%) and gout (4.9%) were significantly more prevalent in those with PsA than those with psoriasis (P < .05). The odds ratio (OR) for PsA is 15.94 in patients with hyperlipidemia (95% CI, 1.64-154.80). The OR for PSA is 3.83 in those with gout (95% CI, 1.19-12.31).

Allergic rhinitis was more prevalent (5.88%) in patients with PsA than patients with psoriasis (P < .01); The OR was 8.17 (95% CI, 2.26-29.50). One possible biomarker, plasma hs-miR-210-3p, separates PsA from psoriasis and can be detected even after treatment with anti-tumor necrosis factor-α agents (P < .05).

Reference

Su Y. Early diagnosis of psoriatic arthritis among psoriasis patients: clinical experience sharing. Clin Rheumatol. Published online May 28, 2020. doi:10.1007/s10067-020-05132-1