Risk factors for repeated dexamethasone intravitreal implant therapy for macular edema due to treatment-naïve branch retinal vein occlusion

Abstract

Background: This study evaluated the effects of dexamethasone intravitreal implant on treatment-naïve branch retinal vein occlusion (BRVO)-induced macular edema (ME), and the risk factors for earlier repeated treatment.

Methods: Patients treated from 2013 to 2016 were enrolled. The patients' demographics, medical history, best-corrected visual acuity (BCVA), and central retinal thickness (CRT) were recorded. Risk factors for repeated treatment were identified using a Cox proportional hazard model and logistic regression.

Results: 29 patients (mean age: 58.64 ± 13.3 years) were included; 44.8% received only one injection, while 55.2% received two or more. The mean initial CRT was 457.8 ± 167.1 μm; the peak CRT and final CRT improved significantly to 248.9 ± 57.9 μm and 329.2 ± 115.1 μm, respectively. The peak BCVA improvement and final improvement were 29.5 ± 23.5 approximate ETDRS letters and 19.8 ± 24.4 letters, respectively, with 62.1% of patients improving by more than 15 letters. Older age, higher initial CRT, and diabetes were the risk factors for multiple injections.

Conclusion: Dexamethasone intravitreal implant results in significant peak CRT and BCVA improvements, while older age, higher initial CRT, and diabetes are risk factors for repeated injections. The optimal retreatment schedule for these patients should be further explored.

Keywords: Age; Branch retinal vein occlusion; Central retinal thickness; Dexamethasone intravitreal implant; Diabetes; Macular edema.

Fig. 1

a CRT showed rapid improvement in the first month. b The improvement in BCVA was significant after 2 months

Fig. 2

a Kaplan–Meier analysis stratified showed that the median time to the second Ozurdex treatment in the group older than 60 years was 3.96 months, whereas the median time to second treatment in the group younger than 60 years was greater than 50 months (p = 0.007). b The median time to the second Ozurdex treatment in the initial CRT > 375 μm group was 4.06 months, whereas the median time to the second treatment in the initial CRT < 375 μm group was greater than 50 months (p = 0.022). c The median time to the second Ozurdex treatment in the diabetes group was 3.93 months, whereas the median time to the second treatment in the patients without diabetes was greater than 50 months (p = 0.003). More than 60% of the patients without diabetes only needed a single injection during the follow-up period, which was a statistically significant difference from the patients with diabetes (p = 0.003)