What Drives Risk of Developing Psoriatic Arthritis from Psoriasis?

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Characteristics such as nail involvement, aged being at least 40 years old, having high-sensitivity C-reactive protein (hs-CRP), or having an elevated erythrocyte sedimentation rate (ESR) may each be independent risk factors for patients with psoriasis to develop psoriatic arthritis (PsA).

Findings from a recent international study sought to identify the possible risk factors driving the transformation of psoriasis into clinical PsA, as well as to explore the clinical value of MRI screening in detecting PsA early.

Investigators from China used a retrospective, longitudinal case–control study design in which they separated their participants into a case group and a control group. These individuals had been patients in the period between 2017 and 2021 at the department of dermatology at Beijing Chaoyang Hospital.

Those who met the research team’s specified criteria for inclusion had been given a first clinical diagnosis of psoriasis. The team’s case cohort was made up of 75 subjects who had been diagnosed with psoriatic arthritis, and the remaining 345 individuals with psoriasis made up the control arm. The team reviewed both cohorts retrospectively from their initial psoriasis vulgaris diagnosis.

The CASPAR criteria were implemented for diagnosis of psoriatic arthritis, with a score of at least three in five categories being necessary for qualification: psoriatic nail dystrophy, evidence of psoriasis (current or familial), a negative rheumatoid factor (RF) test, dactylitis, and radiographic juxta-articular new bone formation. The investigators used a diagnosis by experienced dermatologists as their standard, having any contentious cases assessed by a panel of three experts.

Criteria for inclusion in the study were being within the age range of 18 to 65 years old, having a confirmed psoriasis or PsA diagnosis, informed consent having been signed, and a peripheral joint MRI. The team had several criteria for trial exclusion, some of which included having related arthritic issues, having erythrodermic or pustular psoriasis, malignancies, and others.

The investigators would collect baseline covariates from the subjects’ data. Their analyses—including univariate, multivariate, receiver operating characteristic curves—were carried out to better understand the associated risk factors and evaluate the necessity of psoriasis patient imaging.

The research team’s multivariate logistic regression analysis showed that there were major links between various factors connecting psoriasis to PsA. Some of these were found by the team to be nail involvement, increased hs-CRP levels, being aged at least 40 years, and ESR.

Additionally, the investigators reported that the combination of MRI-detected enthesitis with tenosynovitis as predictive elements indicated strong diagnostic accuracy, with specificity being particularly high (94.3 percent versus 69 percent, respectively). There was also a notably similar sensitivity (89 percent versus 84.6 percent, respectively).

“First, this retrospective study has inherent limitations, such as underlying selection and information biases,” investigators wrote. “Second, this study only examined patients' peripheral joints. Thus, these findings may not be applicable to psoriasis patients with exclusively axial involvement. Third, the conclusions from this single-center study still require external validation.”

An original version of this study was published by sister site HCPLive.