Compliance to intravitreal anti-vascular endothelial growth factors for treatment of retinal diseases in Nigerians: a retrospective multicenter study

BACKGROUND: Little is known about compliance with intravitreal anti-vascular endothelial growth factor (VEGF) therapy for the treatment of macular and retinovascular diseases among Nigerians and Africans. The objective of this study is to measure compliance to 3 or more and 6 or more intravitreal anti-VEGF injections for common macular and retinovascular diseases in Nigerian clinics and evaluate the impact on visual outcomes. METHOD: Retrospective multicenter chart review of 622 eyes/ 528 patients diagnosed with neovascular age-related macular degeneration (nAMD), diabetic macular edema (DME), retinal vein occlusions (RVOs), including branch, central, and hemiretinal (BRVO, CRVO, and HRVO), and non-AMD Choroidal Neovascular Membrane (CNVM) from five clinics (urban, semi-urban, and rural), collecting demographics, diagnosis, injection type/number, pre-/post-BCVA (converted to LogMAR), and follow-up. Treatments were intravitreal Bevacizumab (Avastin), Ranibizumab (Patizra), and Aflibercept (Eylea). Definitions of compliance: compliant; ≥3 injections (standard loading), also ≥ 6 injections. RESULTS: For all 622 eyes, presenting BCVA: 1.21 ± 0.84 and the final BCVA: 0.91 ± 0.80 (P = < 0.001). Overall compliance with ≥ 3 injections was 47.5%, and with ≥ 6 injections, 10.1%. Compliance to ≥ 3 injections by diagnosis was as follows: AMD 50.4%, Non-AMD CNVM 58.2%, BRVO 44.8%, CRVO 44.0%, HRVO 46.7%, DME 40.6%. Age (P = 0.264) and sex (P = 0.870) did not affect compliance to ≥ 3 injections. Clinic location significantly influenced compliance with ≥ 3 injections (P = 0.000), but not with 6 injections (P = 0.173). The highest rates of compliance with ≥ 3 injections were observed in urban tertiary centers. Injection type and cost were not significant factors (P = 0.36). Eyes with ≥ 3 injections achieved better vision (≥ 6/18) across all diagnoses; the most notable improvements were in non-AMD CNVM (+ 41.4%) and BRVO (+ 35%). Statistically significant LogMAR improvements were seen in CRVO (p = 0.049) and DME (p = 0.043). Postoperative endophthalmitis occurred in 2/622 eyes (0.0032) (both Avastin); no other serious adverse event was recorded. CONCLUSIONS: Real-world compliance is significantly lower than ideal. Urban and tertiary clinics show better adherence. Receiving the recommended loading doses is associated with improved visual outcomes for most diagnoses. Understanding the reasons for non-compliance, using a prospective approach, and addressing them will improve treatment outcomes for more Nigerian and presumably African patients receiving anti-VEGF drugs.