Changing Reimbursement Criteria on Anti-VEGF Treatment Patterns Among Wet Age-Related Macular Degeneration and Diabetic Macular Edema Patients: An Interrupted Time Series Analysis

Background: To evaluate the impact of reimbursement criteria change on the utilization pattern of anti-vascular endothelial growth factor (anti-VEGF) among patients with wet age-related macular degeneration (wAMD) and diabetic macular edema (DME) separately in Taiwan. Methods: An interrupted time series analysis (ITSA) was performed using Taiwan’s National Health Insurance (NHI) database, and patients with wAMD or DME diagnosis at the first injection of anti-VEGF agents was identified from 2011 to 2019. The outcome of interest was treatment gaps between injections of anti-VEGF. This outcome was retrieved quarterly, and the study period was divided into three phases in wAMD (two criteria changed in August 2014 [intervention] and December 2016 [intervention]) and two phases in DME (three consecutive criteria changed in 2016 [intervention]). Segmented regression models adjusted for autocorrelation were used to estimate the change in level and the change in slope of the treatment gaps between each anti-VEGF injection. Results: The treatment gaps between each anti-VEGF injection decreased from 2011 to 2019. The cancellation of the annual three needles limitation was associated with significantly shortened treatment gaps between the third and fourth needles (wAMD change in level:-228 days [95% CI-282,-173], DME change in level:-110 days [95% CI-141,-79]). The treatment gap between the fifth and sixth needles revealed a similar pattern but without significant change in DME patients. Other treatment gaps revealed considerable change in slopes in accordance with criteria changes. Conclusion: This is the first nationwide study using ITSA to demonstrate the impact of reimbursement policy on treatment gaps between each anti-VEGF injection. After canceling the annual limitation, we found that the treatment gaps significantly decreased among wAMD and DME patients. The shortened treatment gaps might further link to better visual outcomes according to previous studies. The different impacts from criteria changes can assist future policy shaping. Future studies were warranted to explore whether such changes are associated with the benefits of visual effects.