Background/Purpose:  Adalimumab (ADA) is a TNF-alpha inhibitor indicated for use in various inflammatory autoimmune diseases including rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA). Patients receiving ADA in Canada are eligible to enroll in a patient support program (PSP) providing personalized services including tailored interventions. This retrospective cohort study assessed the impact of specific factors, including PSP services and patient characteristics, on persistence and adherence to ADA.

Methods:  An algorithm based on probabilistic matching was developed to link patients in the ADA PSP database to the IMS Health longitudinal pharmacy transaction database. Patients that started ADA therapy between July 2010 and August 2014 were selected and their prescriptions were evaluated for a period of 12 months after the index date to calculate days until end of persistence (defined by a gap in therapy of ≥90 days), censored for patients who remained on therapy through month 12. Cox proportional hazards modelling provided hazard ratios (HR) for the association between persistence and patient characteristics and PSP services. Adherence, measured by medication possession ratio (MPR), was calculated and multivariable logistic regression provided adjusted odds ratios (OR) for the relationship between high adherence (MPR >= 80%) and patient characteristics and PSP services.

Results:  The linkage algorithm yielded a final sample of 10,857 patients (2,067 RA; 2,499 AS or PsA). Statistically significant differences in the hazard rate of discontinuation and the odds of high adherence were identified across multiple variables. Male patients demonstrated 20% less likelihood of discontinuation (HR = 0.801, p<0.0001) and had a significantly greater odds of adherence (OR = 1.118, p<0.015). Relative to the 30-39 year category, older age groups had significantly greater odds of adherence (40-49, 50-59, 60-69, 70+; OR = 1.247, 1.234, 1.323, 1.411, p<0.01). Patients receiving ongoing motivational interventions, in the form of nurse-provided phone calls, were 72% less likely to cease therapy when compared to those that did not receive the interventions (HR = 0.282, p<0.0001) and were also more adherent (OR = 1.483, p<0.0001). Treatment abandonment (failure to initiate therapy after enrolment in the PSP) was >80% more frequent in patients that did not receive a pre-ADA intervention (p<0.0001).

Conclusion:  Ongoing motivational interventions, as provided by the ADA PSP, were found to have a large and statistically significant association to greater patient persistence and adherence over the first 12 months of treatment. These results may help refine interventions aiming at improving treatment adherence.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/canadian-study-of-outcomes-in-adalimumab-humira-patients-with-support-for-adherence-results-from-the-companion-study/