medwireNews: Among people with peripheral spondyloarthritis (pSpA), those who also have psoriasis show different clinical characteristics to those without the skin condition, study findings indicate.
In addition, the research, which used data from the ASAS-PerSpA study, showed that pSpA patients without psoriasis were less likely to receive biologics despite reporting a similar disease burden to those with psoriasis.
Denis Poddubnyy (Charité – Universitätsmedizin Berlin, Germany) and co-authors report in Rheumatology that 19.2% of the 433 patients with pSpA included in the study had a personal history of psoriasis.
They found that on average, participants with psoriasis were significantly older than those without psoriasis (48.4 vs 43.2 years), had significantly longer symptom duration (14.4 vs 9.0 years) and diagnostic delay (7.4 vs 3.5 years), and had significantly higher rates of dactylitis (36.1 vs 20.0%) and enthesitis (65.1 vs 55.4%).
In patients with psoriasis and dactylitis, fingers were more often affected than toes (76.9 vs 23.1%) whereas the reverse was true for people with pSpA without psoriasis with the fingers less likely to be affected than the toes (47.1 vs 52.9%).
Among the laboratory variables assessed, the researchers observed that the group with psoriasis had a significantly lower prevalence of HLA-B27 positivity (38.3 vs 66.5%), a significantly lower mean level of C-reactive protein (8.5 vs 15.2 mg/L), and a significantly higher rate of rheumatoid factor positivity (7.7 vs 1.3%).
Patient-reported disease activity outcomes such as ASDAS-CRP, BASDAI, and BASFI did not differ significantly between the people with and without psoriasis, but some treatment types did.
Specifically, individuals with psoriasis had a significantly lower rate of local glucocorticoid injection use for musculoskeletal involvement (79.4 vs 98.1%) but a significantly higher rate of biologic use (71.1 vs 46.9%).
“On the one hand these results might indicate that patients with psoriasis were more likely to be treated with [biologics] because of higher severity of musculoskeletal manifestations (especially, enthesitis, and dactylitis),” Poddubnyy et al remark.
“On the other hand, there are currently no approved treatment options for patients with pSpA without a personal or family history of psoriasis and no evidence of axial involvement,” they write.
The investigators say that the lack of approved treatments “might have important implications in clinical practice since early-diagnosed non-psoriatic pSpA patients might experience a substantial delay in the introduction of effective anti-inflammatory drugs.”
Multivariable regression analysis revealed that the presence of psoriasis was associated with a significantly increased likelihood of diagnostic delay and enthesitis, at odds ratios (ORs) of 1.06 and 2.39 per year, respectively. Conversely, there was a significantly decreased risk for HLA-B27 positivity (OR=0.31) in this group.
Poddubnyy and colleagues suggest that focusing “on the treatment of skin condition and a neglecting of musculoskeletal manifestations might be one of the reasons for a longer diagnostic delay” in the patients with psoriasis.
They add: “This may also indicate an unmet need to improve awareness among physicians caring for patients with psoriasis.”
For the patients without psoriasis, the team says that “there is an urgent need for randomized controlled trials with potentially effective [biologics] (IL-17 and IL-23 inhibitors) and targeted synthetic DMARDs (such as Janus kinase inhibitors).”
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