Real-world effects of anti-vascular endothelial growth factor injection frequency on visual outcomes in patients with diabetic macular oedema

Abstract Background and objective Anti-vascular endothelial growth factor (VEGF) injections are often administered less frequently in real-world treatment of diabetic macular oedema (DMO) than what was studied in clinical trials. This study aims to characterise real-world DMO treatment patterns and the effect of treatment intervals on patient outcomes. Study design/patients and methods This was a retrospective study of 291 patients with DMO treated with anti-VEGF therapy. 12- and 24-month best visual acuity (BVA) and central subfield thickness (CST) were compared between injection interval groups, which were determined by averaging the two most recent injection intervals. Multiple linear regressions were performed to identify factors associated with injection interval, BVA, and CST. Results 48.8% of patients received injections less than or equal to every 8 weeks (≤ q8w), 27.5% between every 8 to 12 weeks (q8–12w), and 23.7% greater than every 12 weeks (> q12w). Baseline CST was similar ( p = 0.32), but BVA differed significantly in q8–12w patients ( p = 0.0095). BVA and CST at 12 months were similar, but q8–12w patients experienced greater 12-month BVA improvement (7.36 ± 12.4 letters) than > q12w patients (1.26 ± 12.3 letters; p = 0.0056). 24-month BVA and CST changes were similar between groups ( p = 0.30 and 0.87). Baseline BVA, HbA1c, and sex were associated with 12-month BVA, and baseline BVA and CST were associated with 12-month CST. Conclusion Many patients experienced improvements in BVA and CST over 12 months of treatment despite receiving less frequent anti-VEGF therapy than recommended in the pivotal trials. The present study showed that extended treatment intervals with bevacizumab were effective in preserving vision of many individuals with high baseline BVA.