Comparative safety and efficacy of suprachoroidal versus intravitreal triamcinolone acetonide for diabetic macular edema: a systematic review and meta-analysis

Background Diabetic macular edema is a leading cause of visual impairment in diabetic retinopathy. This systematic review and meta-analysis aimed to compare the safety and efficacy of suprachoroidal vs. intravitreal triamcinolone acetonide delivery in adults with diabetic macular edema. Methods Cochrane Central Register of Controlled Trials, PubMed, Embase, and Scopus were searched from inception to November 2025, for comparative studies evaluating suprachoroidal versus intravitreal triamcinolone acetonide in diabetic macular edema. Four reviewers independently screened and extracted data in pairs, with disagreements resolved by discussion or third-reviewer adjudication. Risk of bias was assessed using design-appropriate Cochrane tools for randomized and non-randomized studies (RoB 2 and ROBINS-I). Results Six studies contributed 600 eyes to the eligible direct comparison. BCVA favored SCTA at 1 month (MD − 0.065 logMAR, 95% CI − 0.121 to − 0.009), 3 months (MD − 0.125, 95% CI − 0.168 to − 0.081), and 6 months (MD − 0.101, 95% CI − 0.126 to − 0.075), although the 1-month estimate was not robust in sensitivity analyses. CMT reduction also favored SCTA at 1 month (MD − 53.6 μm, 95% CI − 90.0 to − 17.3), 3 months (MD − 62.2 μm, 95% CI − 115.6 to − 8.8), and 6 months (MD − 88.6 μm, 95% CI − 110.6 to − 66.6). Mean IOP did not differ significantly at 1 month (MD − 1.49 mmHg, 95% CI − 2.99 to 0.02), 3 months (MD − 2.16, 95% CI − 4.43 to 0.12), or 6 months (MD − 2.36, 95% CI − 5.99 to 1.28). Categorical safety outcomes were sparsely and inconsistently reported. Conclusions While larger-scale studies are needed to confirm these results, our findings suggest that suprachoroidal injections may be associated with better visual and anatomical outcomes over intravitreal injections. However, confidence in the magnitude of benefit is limited by the small evidence base, short follow-up, heterogeneous reporting, and high risk of bias. Safety evidence remains insufficient to establish a definitive advantage. Clinical trial number Not applicable.