Baseline central macular thickness predicts the need for retreatment with intravitreal triamcinolone plus laser...

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.

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.

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.

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.