Baseline central macular thickness predicts the need for retreatment with intravitreal triamcinolone plus laser photocoagulation for diabetic macular edema

Roderick O'Day,¹ Daniel Barthelmes,¹ Meidong Zhu,¹ Tien Yin Wong,^2,3 Ian L McAllister,⁴ Jennifer J Arnold,⁵ Mark C Gillies<sup>1

1</sup>Clinical Ophthalmology and Eye Health, The University of Sydney, Sydney, NSW, Australia; ²Singapore Eye Research Institute, National University of Singapore, Singapore; ³Center for Eye Research Australia, The University of Melbourne, Melbourne, VIC, Australia; ⁴Lions Eye Institute, The University of Western Australia, Perth, WA, Australia; ⁵Marsden Eye Specialists, Sydney, NSW, Australia

Purpose: To identify baseline characteristics that predict the number of treatments with intravitreal triamcinolone acetonide (IVTA) plus laser photocoagulation needed to treat diabetic macular edema over a 2-year period.
Methods: Individual data from 42 eyes of 42 participants treated with IVTA plus laser photocoagulation for diabetic macular edema during a prospective, randomized, double-masked, placebo-controlled trial were used for this post hoc analysis. Baseline characteristics – age, gender, best-corrected visual acuity, glycosylated hemoglobin, phakic status, intraocular pressure, and central macular thickness (CMT) – were correlated with the number of IVTA plus laser treatments received during the 2 years of this study.
Results: The median number of treatments received over the 2-year period was 2.5 (interquartile range 1.0–3.0), with 21 (50%) eyes needing three or more treatments. Eyes that received more IVTA plus laser treatments had a higher mean baseline CMT and eyes with a higher baseline CMT were more likely to receive three or more treatments (odds ratio 5.13, 95% confidence interval 1.75–15.04, P=0.003 per 100 µm increase in CMT). No significant relationship was found between other baseline characteristics and the number of IVTA plus laser treatments received.
Conclusion: Higher baseline CMT was strongly linked with receiving more IVTA plus laser treatments. These patients may be at higher risk of developing dose-dependent steroid-related adverse events, cataract progression, and intraocular pressure rise.

Keywords: diabetic macular edema, intravitreal triamcinolone, central macular thickness