Persistence and treatment-free interval in patients being prescribed biological drugs in rheumatology practices in Germany

Abstract

Aims: The goal of this study was to analyze persistence and the treatment-free interval in patients being prescribed biological drugs in rheumatology practices in Germany.

Methods: Patients who received a first prescription of biological drugs between 2008 and 2016 in 21 rheumatologists in Germany were included in this study (index date). The main outcome was the rate of persistence with biological drugs as a function of the duration of the treatment-free interval used to define discontinuation. The secondary outcomes were the duration of the treatment-free interval, the probability of restarting therapy, and their respective association with age, gender, and diagnosis (i.e., rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis).

Results: A total of 4925 patients were included in this study. After 5 years of follow-up, the rate of persistence was 32.6%, 51.1%, and 65.7% if discontinuation was defined as a gap of 90, 180, and 360 days respectively. The majority of patients restarted therapy between 91 and 180 days after the discontinuation date. Advanced age was associated with a decreased probability of restarting biological therapy after a treatment-free interval of at least 91 days, with odds ratios ranging from 0.34 in people aged 61-70 years to 0.66 in those aged 31-40 years (reference value: ≤ 30 years). Finally, patients over 70 and those suffering from ankylosing spondylitis had shorter treatment-free intervals compared to those 30 years or younger (adjusted difference of - 117 days) and those suffering from rheumatoid arthritis (- 48 days) respectively.

Conclusion: Persistence varied widely depending on the definition of discontinuation, with the majority of nonpersistent patients restarting biological therapy shortly after discontinuation.

Keywords: Biological drugs; Germany; Persistence; Retrospective study; Rheumatology practices; Treatment-free interval.