How early should psoriatic arthritis be treated with a TNF-blocker?

Model to Determine the Cost-Effectiveness of Screening Psoriasis Patients for Psoriatic Arthritis

OBJECTIVE

Screening psoriasis patients for psoriatic arthritis (PsA) is intended to identify patients at earlier stages of the disease. Early treatment is expected to slow disease progression and delay the need for biologic therapy. Our objective was to determine the cost-effectiveness of screening for PsA in patients with psoriasis in Canada.

METHODS

A Markov model was built to estimate the costs and quality-adjusted life years (QALYs) of screening tools for PsA in psoriasis patients. The screening tools included the Toronto Psoriatic Arthritis Screen, Psoriasis Epidemiology Screening Tool, Psoriatic Arthritis Screening and Evaluation, and Early Psoriatic Arthritis Screening Questionnaire (EARP) questionnaires. States of health were defined by disability levels as measured by the Health Assessment Questionnaire. State transitions were modeled based on annual disease progression. Incremental cost-effectiveness ratios and incremental net monetary benefits were estimated. Sensitivity analyses were undertaken to account for parameter uncertainty and to test model assumptions.

RESULTS

Screening was cost-effective compared to no screening. The EARP tool had the lowest total cost ($2,000 per patient per year saved compared to no screening) and the highest total QALYs (additional 0.18 per patient compared to no screening). The results were most sensitive to test accuracy and the efficacy of disease-modifying antirheumatic drugs (DMARDs). No screening was cost-effective (at $50,000 per QALY) relative to screening when DMARDs failed to slow disease progression.

CONCLUSION

If early therapy with DMARDs delays biologic treatment, implementing screening in patients with psoriasis in Canada is expected to represent a cost savings of $220 million per year and improve the quality of life.

Steps in the management of psoriatic arthritis: a guide for clinicians

Psoriatic arthritis is a common systemic inflammatory disorder, which in addition to skin and nail involvement may be associated with peripheral and axial joint involvement, enthesitis, dactylitis, and important comorbidities - especially cardiovascular morbidity. Better insights into the involved pathogenic mechanisms have resulted in an improved therapeutic armamentarium, which targets key pathways in its pathogenesis. This has resulted in significant clinical responses to newer therapeutic agents, especially those directed at inhibition of tumor necrosis factor α. Biological therapy leads to significant levels of remission, improved quality of life, and retards or improves structural radiological damage.

[Diagnosis and therapy of early psoriatic arthritis]

Early diagnosis of psoriatic arthritis is of importance because an erosive disease is already detectable after a 2-year duration of symptoms. Often psoriatic arthritis cannot easily be detected because of the diversity of disease manifestations in early stages. As up to 30% of psoriasis patients develop psoriatic arthritis an interdisciplinary dermatologic/rheumatologic approach to diagnose findings and treatment decisions would be desirable. Screening tools, such as validated questionnaires allow an early detection and selection of patients with a high probability of psoriatic arthritis even in dermatological care or on a house physician basis. The implementation of the CASPAR criteria as a classification tool for psoriatic arthritis has also improved the diagnosis finding in patients with a recent onset of active musculoskeletal disease. Data from early psoriatic arthritis cohorts illustrate that drug-free remission is rare. An adequate treatment is of importance. The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) has developed treatment recommendations based on the available evidence for different treatment modalities.