Despite some clues, scientists don’t yet understand which patients with psoriasis are likely to eventually develop psoriatic arthritis; solving that riddle could have major impacts on patient care.
Scientists know that as many as 3 in 10 patients with psoriasis (PsO) will eventually go on to be diagnosed with psoriatic arthritis (PsA), yet figuring out which patients are most likely to transition to the more serious disease remains a steep and unsolved challenge.
In a new review article, published in Current Rheumatology Reports, Dennis McGonagle, PhD, of the University of Leeds, in the United Kingdom, and colleagues sought to understand what the existing scientific literature might explain about the utility of imaging in deciphering which patients were likely to develop PsA, and potentially, how it might one day be prevented.
McGonagle told The American Journal of Managed Care® (AJMC®) in an email that investigators have a long way to go. For instance, he noted that symptoms like non-specific or brief-duration arthralgia have been associated with PsA, but arthralgia alone is an insufficient marker.
“A lot of work needs to be done because patients with psoriasis and arthralgia may have other diagnoses like OA (osteoarthritis), fibromyalgia, and multiple mechanical pains,” McGonagle told AJMC® . “We don’t have an antibody test like ACPA (anti-citrullinated protein antibodies) in pre-RA (rheumatoid arthritis) where ACPA+ and arthralgia indicate that up to 50% of cases will develop RA in the next year.”
Further complicating matters, McGonagle noted that PsO may predate PsA by 10-15 years. In the review, McGonagle and colleagues write that tenosynovitis and enthesitis determined by sonography are the key imaging features present in non-specific PsO arthralgia patients at risk for future PsA.
“Psoriasis patients with arthralgia have a higher prevalence of tenosynovitis and imaging enthesopathy is at a higher risk of transitioning to overt PsA,” McGonagle and colleagues write in the review.
The investigators also note that reports indicate that the early phases of PsA are complicated by factors like body mass index (BMI). Yet, while BMI is a risk factor for PsA, it has also been associated with imaging abnormalities on enthesopathy, the authors write.
“Fully disentangling these clinical and imaging factors will be important for imminent PsA so that disease prevention strategies can be investigated,” the investigators write.
Thus, McGonagle told AJMC that the search for an imaging biomarker is ongoing. In the meantime, he said the existing literature is not sufficient to enable a personalized medicine approach. He said there are some patterns of PsO, such as nail disease and also the extent of PsO that appear to predict risk, but he said such data points are only meaningful at a population level and thus can’t be translated to calculate an individual patient’s risk.
Though much more research is needed, he said the upside of successfully identifying a more precise biomarker for PsA would be considerable.
“The ability to define cases at risk of PsA would drive the use of therapy for psoriasis that might prevent arthritis onset,” he said. McGonagle said one important vein of research is to see whether treating patients with PsO with therapies that are also approved for PsA might actually result in stopping the evolution to arthritis.
Zabotti, A., Tinazzi, I., Aydin, S.Z. et al. From psoriasis to psoriatic arthritis: Insights from imaging on the transition to psoriatic arthritis and implications for arthritis prevention. Curr Rheumatol Rep. Published online May 16, 2020. doi:10.1007/s11926-020-00891-x