Intravitreal ranibizumab alone or in combination with panretinal photocoagulation for the treatment of proliferative diabetic retinopathy with coexistent macular edema: long-term outcomes of a prospective study

Abstract

Aims: To compare intravitreal ranibizumab as monotherapy or in combination with panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PDR) and coexistent diabetic macular edema (DME) in a long-term follow-up of 24 months.

Methods: Participants in this prospective study were 47 patients with PDR and concurrent DME, who were randomized at baseline into two groups: (i) the "ranibizumab alone" group (n = 23), which was treated with at least 3 intravitreal ranibizumab injections as a loading phase, and (ii) the "combination" group (n = 24), which was treated with PRP and at least 3 intravitreal ranibizumab injections. Thereafter, all patients were followed up at a pro re nata (PRN) basis, with regular monthly monitoring for 24 months. At each visit, best corrected visual acuity (BCVA) and spectral domain-optical coherence tomography were performed, while regression of neovascularization was also recorded.

Results: The "combination" group had better control of neovascularization and less events of vitreous hemorrhage than ranibizumab alone through the 2 years. BCVA did not differ significantly between the two groups at months 12 and 24 of the follow-up. The "ranibizumab" alone group presented greater reduction in central retinal thickness at month 12, which did not reach significance at month 24 compared to "combination" group. Greater number of injections was needed in the monotherapy group (mean 14 injections) compared to "combination" group (mean 11 injections) through month 24.

Conclusions: Both intravitreal ranibizumab alone or in combination with PRP could be used effectively for the treatment of PDR and coexistent DME. Even though there was no difference in BCVA and CRT at the 24-month follow-up between the two groups, the combination group presented greater regression of neovascularization with less injections.

Keywords: Anti-VEGF; Diabetic macular edema; Optical coherence tomography; Proliferative diabetic retinopathy; Ranibizumab; Treatment.