Biological therapy in the treatment of psoriatic arthritis: economic and epidemiological considerations

ABSTRACT

Background: Biological therapies have a significant economic and clinical burden but, in general, lose their effectiveness over time. This study evaluated the medication persistence and costs associated to use of anti-TNF agents for psoriatic arthritis (PsA) treatment.

Methods: A historical cohort composed of individuals in Brazil with PsA diagnosis was developed during the period between 2010 and 2015. The difference among the anti-TNF agents was verified by the log-rank test. The predictors of medication non-persistence were identified by Cox regression. The costs were compared by variance analysis with Bonferroni correction.

Results: 11,008 patients were analyzed. Adalimumab (51%) was the most used anti-TNF agent. Individuals using adalimumab presented higher medication persistence as compared to etanercept and infliximab. The costs with anti-TNF agents corresponded to 90% of the total costs and were similar among anti-TNF agents. The non-persistence predictors were female sex, younger patients, to live in the Northeastern and Northern regions of Brazil, to use infliximab and etanercept, and have more comorbidities.

Conclusion: The direct costs with anti-TNF agents were the main component of total costs. Outpatient and inpatient costs increase when medication persistence decreases. A considerable price reduction of anti-TNF agents has been observed over the years.

KEYWORDS:

• Psoriatic arthritis
• medication persistence
• costs
• anti-TNF agents

Article highlights

• A total of 11,008 individuals started the first line of biological therapy.

• Patients using adalimumab had the highest medication persistence, whereas those using infliximab had the lowest persistence.

• The medication non-persistence predictors in all periods were to live in poorest regions, to have comorbidities, lower age, and use of etanercept and infliximab.

• The medication persistence was lower in Brazil than in other countries.

• The direct costs with anti-TNF agents corresponded to approximately 90% of the total costs of the PsA treatment.

• Outpatient and inpatient costs increase when medication persistence decreases.

• A considerable price reduction of anti-TNF agents has been observed over the years (40.4% for infliximab, 56.9% for etanercept, and 65.7% for adalimumab).

• The annual costs with anti-TNF agents in Brazil were similar to those described in the United Kingdom and higher than the United States.

Author contributions

Da Silva MRR extracted and analyzed the data and wrote the manuscript; Dos Santos JBR analyzed the data and wrote the manuscript; Almeida AM designed the study and revised the manuscript; Guerra Junior AA designed the study and prepared the data; Alvares Teodoro J designed the study and revised the manuscript; Acurcio FA designed the study and revised the manuscript. All authors agree to be accountable for all aspects of the work.

Acknowledgments

Da Silva MRR and Dos Santos JBR thank the Coordination of Improvement of Higher Education Personnel for granting doctoral scholarships. The authors thank the institutional support of the Collaborating Center of SUS: Technology Assessment and Excellence in Health.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.