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In a recent study, investigators found that age 40 years and older, nail involvement, elevated erythrocyte sedimentation rate (ESR), and elevated high-sensitivity C-reactive protein (hs-CRP) were identified as risk factors for the transformation of psoriasis (PsO) into psoriatic arthritis (PsA).¹ In addition, the researchers believe that magnetic resonance imaging (MRI) may be helpful in the early detection of PsA.¹

Approximately 30% of patients with psoriasis (PsO) progress to the oftentimes debilitating condition of psoriatic arthritis (PsA).² However, since the development of arthritis symptoms frequently lags behind that of skin lesions, early diagnosis of PsA becomes difficult.³

The authors of this new study published in the International Journal of Dermatology believe both timely diagnosis and early intervention are essential for PsA.¹ Magnetic resonance imaging (MRI) and ultrasound (US) are 2 modalities recently recognized as reliable, non-radiative, non-invasive tools for assessing inflammatory arthritis.¹ The European League Against Rheumatism (EULAR) recommends MRI as a method to assess peripheral spondyloarthritis, and it is being increasingly used to evaluate and detect rheumatoid arthritis and other inflammatory joint diseases.^1,4

To that end, Amin Yao, from the department of dermatology at the Third Affiliated Hospital of Sun Yat-sen University in Guangzhou, China, and colleagues recently conducted this retrospective, longitudinal study with the aim of identifying risk factors to aid in early PsA detection and also see whether MRI could assist with disease detection. The study, conducted at the Beijing Chao-yang Hospital from January 2017 to December 2021, included 75 patients clinically diagnosed with PsA (PsA group), as well as a control group of 345 patients with PsO but without PsA (PsO group).¹

The PsO group was comprised of 59% male and 41% female patients (average age, 39.98 years). The PsA group was 60% male and 40% female (average age, 51.67 years). Lifestyle habits, including smoking and drinking, were found to be more common in the PsO group when compared to the PsA group (both P<.01). In contrast, PsA patients had higher BMIs compared with PsO patients, which increased their risk of obesity (P<.05). Patients with PsA had a later disease onset compared with the PsO group (37.45 vs 28.49 years, respectively), and their course of disease also was longer, at 11 years vs 8 years. They also had a higher family history of PsO or PsA than the group with PsO and had a higher incidence of metabolic syndrome (29.73% vs. 3.82%, P<.05).¹

The patients with PsA had more nail involvement than the group with PsO (66.67% vs 21.45%, P>.05), but no significant difference existed in scalp involvement or PASI score. All patients underwent an MRI scan, which revealed a higher incidence of enthesitis in the PsA group (56% vs 1.16%, P<.01), as well as higher incidences of synovitis, tenosynovitis, and bone edema and erosion (P<.01 for all).¹

Univariate logistic regression analysis was used to examine possible variables that might signal an advance from PsO to PsA. Then, multivariate logistic regression analysis was performed to review these more closely and found that independent risk factors for progression from PsO to PsA included age 鈮�40 (P<.01), nail involvement (P<.01), erythrocyte sedimentation rate (ESR) (P<.05), and elevated high-sensitivity C-reactive protein (hs-CRP) (P<.01).¹

Since enthesitis and tenosynovitis showed as more significant in the PsA group in the MRI scans, these were also added to the combined predictors, to determine the effectiveness and efficiency of MRI examination for joint damage in PsO. Furthermore, according to the authors, their study found that 鈥淢RI provides additional value for the early recognition of PsA.鈥� In fact, when MRI-detected enthesitis was combined with MRI-detected tenosynovitis, diagnostic efficacy increased with an improvement in specificity (94.3% vs 69%) and similarities in sensitivity (89% vs 84.6%). The areas under the ROC curve (AUCs) were also found to be highly significant at 0.925 (P<0.01) and 0.858 (P<0.01).¹

But do these findings suggest a role for MRI as screening test in patients with PsO?

鈥淲ithout longitudinal data it's hard to say if they are really detecting cases early or not and if early MRI would actually be helpful,鈥� said Christopher Sayed, MD, a professor in the department of dermatology at the University of North Carolina School of Medicine in Chapel Hill. 

鈥淚 think what they've done is characterized MRI features associated with PsA symptoms, and future longitudinal studies may help identify what proportion of patients with signs of inflammation on MRI in the absence of PsA symptoms might go on to develop PsA in the future. This may be particularly useful in those with multiple of the risk factors that they describe without clinical signs of joint inflammation. Its use as a broad screening tool for all PsO patients may be limited given that the overall rates of detecting joint inflammation with MRI in the PsO group were low and should be weighed against the cost of routine MRI screening,鈥� Dr. Sayed, who was not involved in the study, added.

Regarding their findings of risk factors, the authors acknowledge that some, such as nail bed involvement and high levels of hs-CRP and ESR, support previous research.¹ However, other previous findings, such as smoking, obesity, and family history, were not supported by their data, possible due to differences in research methods or sample sizes. Other limitations noted included selection and information biases, the fact that this study examined only patients鈥� peripheral joints, and that this was a single-center study.¹

Published: June 20, 2024