ATLANTA – Psoriasis type and patient age at presentation among patients with psoriatic arthritis predict the timing of arthritis symptom synchronicity, according to findings from the Psoriatic Arthritis Registry of Turkey International Database.
However, in those who develop arthritis symptoms first, age at onset is not predictive of psoriatic arthritis (PsA) symptom synchronicity, Umut Kalyoncu, MD, reported at the annual meeting of the American College of Rheumatology.
Of 1,631 patients from the registry, 1,251 had psoriasis first, 71 had arthritis first, and 309 had synchronous onset, which was defined as the onset of both psoriasis and arthritis symptoms within a 12-month period. The time from skin disease to PsA was 155.6 months, –67.4 months, and 1.8 months, among the groups, respectively, and the mean age at PsA onset was similar, ranging from about 41 to 42 years in those who developed arthritis first, said Dr. Kalyoncu, of the department of rheumatology at Hacettepe University, Ankara, Turkey.
However, the mean age of PsA onset among those who developed psoriasis first was 29.4 years, compared with 46.3 years in those who developed arthritis first.
“So there is a really big difference between psoriasis beginning age,” he said.
PsA types also differed by onset symptoms: Axial involvement was more common with arthritis-first onset at 38.0%, compared with 28.8% for psoriasis first and 27.8% for synchronous onset). Oligoarthritis occurred more often with arthritis-first onset (45.1% vs. 30.7% and 29.4%, respectively), and polyarthritis occurred less often with arthritis-first onset (33.8% vs. 49.4% and 47.6%, respectively), he said.
Psoriasis type also differed among the groups: Pustular skin involvement was more common in arthritis-first patients (18.3% vs. 11.9% and 16.5% of psoriasis-first and synchronous-onset patients), scalp lesions as the initial lesion were more common in psoriasis-first patients (48.3% vs. 35.2% of arthritis-first patients and 39.8% of synchronous-onset patients), and genital involvement was present more often in arthritis-first patients (12.7% vs. 6.2% and 4.9% of psoriasis-first and synchronous-onset patients).
Early-onset (type 1) psoriasis was more common in psoriasis-first patients (74% vs. 28.1% and 51.8% of arthritis-first and synchronous-onset patients), whereas late-onset (type 2) psoriasis was more common in arthritis-first patients (71.9% vs. 26.0% and 48.2% for psoriasis-first and synchronous-onset patients).
A family history of psoriasis or PsA was more common in psoriasis-first patients (35.6% vs. 26.3% and 28.2% of arthritis-first and synchronous-onset patients), Dr. Kalyoncu said.
Treatment types did not differ between the groups.
Multiple linear regression analysis for the time elapsed from psoriasis to PsA symptom synchronicity, with all other independent variables set to baseline values, showed an overall intercept interval of 66 months, but with nail involvement, family history, or plaque psoriasis, the interval was extended by 28, 24, and 20 months, respectively. However, the presence of pustular psoriasis decreased the intercept interval by 28 months.
A temporal relationship between the onset of skin psoriasis and PsA is a well-known feature of psoriatic disease, with prior studies showing that the majority of cases involve psoriasis-first onset, Dr. Kalyoncu said, adding that heterogeneity in musculoskeletal and skin involvement is also a known feature.
However, little is known about the role of genetics, he noted.
Therefore, he and his colleagues used the Psoriatic Arthritis Registry of Turkey International Database, which was established in 2014 and now also includes data from patients in Canada and Italy, to explore the associations between disease characteristics and the temporal relationship of skin and musculoskeletal disease.
Based on the findings, age at the onset of psoriasis was the main factor that determined PsA symptom synchronicity, he said.
“We know that HLA-Cw6 is important in genetic susceptibility of psoriatic arthritis, but it is important only for early-onset arthritis, not late-onset psoriasis,” Dr. Kalyoncu said. “So our results make an indirect contribution [to the understanding of] these genetic and immunochemical differences between early-onset and late-onset psoriasis, and we need further future studies about this topic.”
Dr. Kalyoncu reported having no relevant disclosures.
SOURCE: Kalyoncu U et al. Arthritis Rheumatol. 2019;71(suppl 10), .