, in a study of 464 adults.
Epidemiologic data show that PsA may be diagnosed as long as 5-10 years after a diagnosis of plaque psoriasis, but PsA ultimately occurs in up to 25% of cases, wrote the study investigators, Paolo Gisondi, MD, of the section of dermatology and venereology, department of medicine, at Università degli Studi di Verona, Italy, and colleagues.
“The delay between the onset of skin manifestations of psoriasis and joint disease may provide a therapeutic window of clinical opportunity for preventing the progression from psoriasis to PsA,” but the impact of continuous systemic treatment with biological disease-modifying antirheumatic drugs (DMARDs) has not been well studied, the researchers said.
In the retrospective, nonrandomized published in Annals of the Rheumatic Diseases, the researchers reviewed data from adults with moderate to severe plaque psoriasis who received continuous treatment with biologic DMARDs, compared with those who received narrow-band ultraviolet light B (nb-UVB) phototherapy, between January 2012 and September 2020.
Patients with a past or present PsA diagnosis were excluded from the study. A total of 234 patients were treated with biologic DMARDs for at least 5 years and 230 were treated with at least three courses of nb-UVB phototherapy; all patients were followed for an average of 7 years.
PsA was determined based on the Classification for Psoriatic Arthritis criteria. Incidence was defined in terms of cases per 100 patients per year.
During the follow-up period, 51 patients (11%) developed incident PsA: 19 (8%) in the biologic DMARDs group and 32 (14%) in the nb-UVB phototherapy group. The annual incidence rate of PsA was 1.20 cases per 100 patients per year in the biologic DMARDs group compared with 2.17 cases per 100 patients per year in the phototherapy group (P = .006).
In a multivariate analysis, independent risk factors for PsA were older age (adjusted hazard ratio, 1.04; P < .001), nail psoriasis (aHR 3.15; P = .001), and psoriasis duration greater than 10 years (aHR, 2.02; P = .001). Most other baseline demographics, including smoking status, baseline Psoriasis Area and Severity Index (PASI) scores, and comorbidities, were similar in patients who did and did not develop PsA.
Of the patients taking biologic DMARDs, 39 (17%) were treated with infliximab, 17 (7%) with etanercept, 67 (29%) with adalimumab, 50 (21%) with ustekinumab, and 61 (26%) with secukinumab; 35 of these patients switched biologics during the study period.
The study findings were limited by several factors including the retrospective design and the resulting potential for biases, notably the potential confounding bias by indication because of the lack of randomization, the researchers noted. Another limitation was the inability to perform a subgroup analysis of biologic DMARD classes because of the small sample size, the authors said. However, they added, the findings were strengthened by the complete database and accurate PsA diagnoses supported by an expert rheumatologist.
Larger prospective and intervention studies are needed to validate the results, the researchers emphasized. However, data from the current study suggest that continued treatment with biologic DMARDs “may reduce the risk of incident PsA in patients with moderate to severe chronic plaque psoriasis,” they concluded.
The study was supported by the European Union’s Horizon 2020 Research and Innovation Program. Dr. Gisondi and several coauthors disclosed relationships with Abbvie, Almirall, Amgen, Janssen, Leo Pharma, Eli Lilly, Novartis, Pierre Fabre, Sandoz, Sanofi, and UCB. The study was supported by the European Union’s Horizon 2020 Research and Innovation Program.