Approximately 3 out of 4 Canadians with PsA Failed to Achieve MDA within 6 months of Treatment

Dafna D Gladman, MD

Credit: University Health Network (UNH)

In Canada, the proportion of patients with psoriatic arthritis (PsA) who were unable to achieve minimal disease activity (MDA) within 6 months ranged from 64.8% to 75.0%, according to a study published in The Journal of Rheumatology.¹ These findings underscore the substantial burden and the unmet need for improved therapies among this patient population.

Although there is no set standard on how to define remission in PsA, MDA is often considered a treatment target. MDA is described as meeting ≥ 5 of 7 the following criteria: Psoriasis Activity and Severity Index (PASI) ≤ 1 or body surface area (BSA) ≤ 3%, tender joint count (TJC) ≤ 1, swollen joint count (SJC) ≤ 1, patient pain visual analogue score (VAS) of ≤ 15 mm, patient global disease activity VAS of ≤ 20 mm, tender entheseal points ≤ 1.19, and a health assessment questionnaire (HAQ) score ≤ 0.5. Additionally, the Disease Activity Index for Psoriatic Arthritis (DAPSA) was created to address the peripheral arthritis domain, and has been used to determine low disease activity (LDA).²

“Notwithstanding how remission is defined in PsA, there is a key knowledge gap in understanding and quantifying the residual disease activity and ongoing burden of disease in patients with PsA,” wrote Dafna D Gladman, MD, associated with the University of Toronto, Department of Medicine, Division of Rheumatology, in Canada, and colleagues. “The skin and joint inflammation characteristic of PsA is often significant, with negative impacts on quality of life. Additionally, these patients have high rates of healthcare utilization24 and disability, and it has been surmised that ongoing systemic inflammation can worsen the severity of other comorbidities.”

The multi-region, observational, retrospective analysis explored patient data from the Rhumadata and International Psoriasis and Arthritis Research Team (IPART) cohorts. Adult patients who had initiated advanced therapy for the treatment of PsA between January 2010 and December 2019 were included in the study. The primary endpoint was the proportion of patients who were unable to achieve MDA within a 6-month timeframe, while secondary endpoints focused on patient-reported and clinical burden of disease. Statistics included information on the number of prior advanced therapies, treatment class, and summarized data by region.

A total of 1596 patients were included in the analysis, of which 57.0% (n = 909) were from IPART and 43.0% (n = 687) were from Rhumadata. The mean age was comparable across regions and ranged from 47.6 years (Western Canada) to 51.1 years (Atlantic/East). Most patients were from Québec (43.0%), followed by Ontario (39.4%), Atlantic/East (10.3%), and Western Canada (7.2%).

Among Canadian regions, the proportion of patients who failed to achieve MDA was 64.8% in Ontario, 68.3% in Western Canada, 74.8% in Québec, and 75.0% in the Atlantic/East region. Failure to achieve MDA was more likely among patients treated with an interleukin-17 (IL-17) inhibitor when compared with a tumor necrosis factor (TNF) inhibitor in all regions except for Atlantic/East. At the 6-month mark, between 73.2% to 78.6% of patients reported pain and continuing functional impairment ranged from 24.0% in the West region to 83.3% in the Atlantic/East region.

Investigators noted limitations including the real-world, retrospective study design, which was non-randomized, uncontrolled, and could not be used to determine causal associations. An additional limitation was missing data, which hindered the interpretation of certain endpoints.

“There was considerable variability noted in outcomes and level of burden of disease by region, which merits further study,” investigators concluded. “These results highlight the need for earlier diagnosis, earlier access to advanced therapies, better access to imaging across the country, as well as improved therapeutic approaches to enhance outcomes for Canadians living with PsA.”

References

1. ^{Gladman DD, Chandran V, Rosen CF, et al. Residual Disease Activity In Canadian Patients With Psoriatic Arthritis (PsA) Treated With Advanced Therapies: Results From A Multi-Registry Analysis (UNISON-PsA). J Rheumatol. Published online February 15, 2024. doi:10.3899/jrheum.2023-0716}
2. ^{Schoels M, Aletaha D, Funovits J, Kavanaugh A, Baker D, Smolen JS. Application of the DAREA/DAPSA score for assessment of disease activity in psoriatic arthritis. Ann Rheum Dis 2010;69:1441-7.}