IntravitrealBevacizumabInjectionAloneorCombined withTriamcinoloneVersusMacularPhotocoagulationIn BilateralDiabeticMacularEdema;ApplicationofBivariate GeneralizedLinearMixedModelwithAsymmetric RandomEffectsinaSubgroupofaClinicalTrial

Abstract Purpose: Tocomparetheefficacyof intravitrealbevacizumab (IVB) injectionalone orwithintravitrealtriamcinolone acetonide (IVB/IVT) versus macular photocoagulation (MPC) in bilateral diabetic macular edema (DME). Methods: In this study we revisiteddata from a subsetof subjectspreviouslyenrolledin a randomizedclinical trial. The originalstudy included150 eyes randomizedto three treatmentarms: 1.25 mg IVB alone, combined injectionof 1.25mgIVB and 2 mgIVT,and focalormodified grid MPC.Toeliminatethe possibleeffects ofsystemic confounders,we selected fellow eyes of bilaterallytreated subjects who had undergone different treatments; eventually30 eyes of 15 patients were re‑evaluatedat baseline,6, 12, 18, and 24 months. Using mixed model analysis,wecomparedthetreatmentprotocolsregardingvisualacuity(VA)andcentralmacularthickness(CMT). Results: Improvement in VA in the IVB group was significantlygreater compared to MPC at months 6 and 12 (P = 0.037 and P = 0.035, respectively) but this difference did not persist thereafter up to 24 months. Other levels of VA were comparable at different follow‑up intervals (all P > 0.05). The only significantdifference in CMT was observed in favor of the IVB group as compared to IVB/IVT group at 24 months (P = 0.048).