Treatment effects of panretinal photocoagulation or combined anti-vascular endothelial growth factor therapy for proliferative diabetic retinopathy on the risks of diabetic macular edema and vitreous hemorrhage

Introduction: This study evaluated the effect of panretinal photocoagulation (PRP) or combined both anti-VEGF therapy and PRP in proliferative diabetic retinopathy (PDR) on the risk of diabetic macular edema (DME) or vitreous hemorrhage (VH) and compared functional, anatomical outcomes and additional treatments in the two groups. Methods: This retrospective analysis involves patients treated for PDR with either PRP alone or in combination with three consecutive anti-VEGF injections, followed for at least 12 months. Treatment effects and other factors associated with the risk of first DME and VH were assessed. Results: We identified 95 eyes from 69 patients (combined group: 37 eyes from 25 patients; PRP group: 58 eyes from 44 patients). At one year the cumulative incidences of the first DME and VH were 8% and 19% (combined group), and 31% and 19% (PRP group), respectively. Combined treatment reduced the risk of first DME after adjusting for age, HbA1c level, PDR severity, and baseline CRT (csHR: 0.211, 95% CI: 0.064–0.700, p=0.011). Increased DME risks correlated with poor blood sugar control (HbA1c ≥8.4%), thicker baseline CRT in non-high-risk PDR, and baseline CRT <232μm in high-risk PDR. The risk of first VH decreased with age (csHR: 0.966, 95% CI: 0.933–0.999, p=0.045). The combined group exhibited superior best-corrected visual acuity at the third and twelfth months. The combined group were less likely to require additional treatment within one year (adjusted OR: 0.254, 95% CI: 0.088–0.739, p=0.011). Conclusion: Combining anti-VEGF agents with PRP effectively reduced the risk of DME, yielding improved visual outcomes and fewer additional treatments within one year.