Evaluation of intravitreal injection of bevacizumab (Avastin) in treatment of diabetic macular edema

Diabetic macular edema (DME) is the most common cause of reduced vision in diabetic patients. With regards to its prevalence and its severe morbidity, attention to new methods of treatment like anti-vascular endothelial growth factor (VEGF) therapy is of great importance. Therefore, this study aimed to evaluate the efficacy of intravitreal injection of bevacizumab (Avastin) in the treatment of diabetic macular edema. METHODS: This prospective clinical trial was conducted on patients with DME who referred to Feiz Hospital, Isfahan, Iran, during 2007-8. The subjects were selected using simple sampling method. Eligible patients underwent a complete ophthalmic examination including optical coherence tomography (OCT) before injection. The treatment was performed through 3 intravitreal injections of 1.25 mg Avastin. There was a 1-month interval between very two injections. A second OCT was obtained 4 weeks after the last injection and the changes in macular thickness were compared using statistical analyses. RESULTS: This study was conducted on 52 eyes of 28 patients (17 men and 11 women) with the mean age of 62.60 ± 7.80 years (range: 45-80 years). The mean macular thickness increased from 259.19 ± 75.9 microns before injections to 265.94 ± 109.40 after 3 injections (p = 0.48). In case to case comparisons, macular thickness reductions were observed in 31 cases from 2 to 74 microns (mean: 24.60 ± 20.85). In 21 cases on the other hand, macular thickness increased from 1 to 324 microns (mean: 52 ± 88.20). Macular thickness before injection was 261.22 ± 77.79 microns in men and 255.95 ± 74.67 in women (p = 0.81). After injections, the values changed to 276.44 ± 122.79 microns in men and 249.15 ± 83.94 in women (p = 0.34). CONCLUSIONS: Intravitreal Avastin is not effective in reducing macular thickness after 4 weeks of injection. In contrast, according to other studies, it seems to be temporarily effective. Therefore, it is better to be combined with other routes of therapy, e.g. laser and intravitreal steroid, in the management of DME.