Intravitreal corticosteroids improve best-corrected visual acuity (BCVA) for patients with diabetic macular edema (DME), and higher doses provide the greatest benefit, according to a meta-analysis published in Eye and Vision. Researchers add that triamcinolone acetonide (TA) is an equally efficacious yet lower-cost alternative to fluocinolone acetonide (FA) or dexamethasone (DEX) implants for treating DME.
Investigators reviewed 19 randomized controlled trials that involved 2839 eyes with DME. They found that intravitreal TA injections, FA implants, and DEX implants could improve BCVA both short-term and long-term in patients with DME. Higher doses of corticosteroids (TA ≥4 mg, FA implant of 0.5 μg/day, and DEX implant of 700 μg) proved more effective at improving BCVA within 6 months after treatment. While all intravitreal corticosteroids reduced central macular thickness, the data suggests intravitreal TA injections of 8 mg or greater work best at improving BCVA within 6 months of the first injection.
Data about changes in intraocular pressure (IOP) during treatment were only available for intravitreal TA injections (and different dosages of TA did not show significant differences in increasing IOP). As such, the long-term efficacy and safety of different corticosteroids merit further study, according to the research team.
“The water solubility of TA is only 20% that of DEX, leading to an extended presence in the vitreous,” investigators report. For this reason, TA (unlike DEX and FA) can be used without a sustained-release delivery system. “Although a single injection of TA can meet the short-term clinical requirement for treating DME, the maximum dose and maximum duration of drug release are limited.”
This study is not without limitations. First, researchers used the mean changes in BCVA instead of the number of patients with improved BCVA as the study outcome. Second, the standard deviation of the mean difference was not reported in some studies included in the review. Third, most trials included in the analysis used time-domain OCT to measure the CMT, while some trials used different devices. Fourth, only one study (with a relatively small sample size) investigated the effect of intravitreal TA injections on long-term BCVA. Fifth, the follow-up period varied among the included from 3 to 39 months. Last, as previously mentioned, the short-term change in IOP was only reported in studies involving TA studies.
Gao L, Zhao X, Jiao L, et al. Intravitreal corticosteroids for diabetic macular edema: a network meta-analysis of randomized controlled trials. Eye and Vis. Publishing online October 11, 2021. doi:10.1186/s40662-021-00261-3