Importance of Treatment Duration: Unmasking Barriers and Discovering the Reasons for Undertreatment of Anti-VEGF Agents in Neovascular Age-Related Macular Degeneration.

Purpose: Since non-adherence (NA) to intravitreal therapy with VEGF drugs is one of the most important modifiable factors compromising treatment outcome of nAMD, the purpose of this study was to investigate the contributing factors and barriers during long-term nAMD treatment.

Methods: Barriers and potential reasons for NA were prospectively measured using the Adherence Barriers Questionnaire Intravitreal Therapy (ABQ-IVT). A random sample of patients receiving intravitreal therapy was drawn based on data for different treatment periods. Three age-sex matched groups included the treatment periods of ≤30 months (group 1), between >30 months and ≤60 months (group 2), and >60 months (group 3). The occurrence of gaps between treatments and/or OCT visits was evaluated.

Results: NA with gaps of >56 days after the scheduled appointment was detected in 39%, 89%, and 100% of patients in group 1, 2, and 3, respectively (groups 1 and 2 vs group 3, p < 0.001). Two or more of such gaps were observed in 6%, 72%, and 94% of patients in group 1, 2, and 3, respectively. The overall ABQ-IVT score showed corresponding differences between the groups: 25.89 ± 7.68 (group 1, 95% CI 22.07-29.71), 34.72 ± 10.32 (group 2, 95% CI: 29.59-38.86), and 33.28 ± 9.04 (group 3, 95% CI 28.78-37.77). Accordingly, the score was inversely correlated with the number of regular follow-up visits in groups 2 and 3 (Pearson correlation coefficient r = -0.65 (p = 0.003) and r = -0.5 (p = 0.034), respectively). Within the groups of longer treatment duration, univariate logistic regression analysis showed higher odds of time commitment and challenge accompanying person to be relevant barriers.

Conclusion: NA is an arising problem with increasing duration of intravitreal therapy. Treatment barriers, detected by the ABQ-IVT, might change or increase during the course of the treatment.