Comparison of Outcomes in the Use of Intravitreal Bevacizumab Vs. Triamcinolone for Patients with Diabetic Macular Edema at the Time of Cataract Surgery (The DiMECAT Trial)

Abstract

Purpose: Cataract surgery in diabetic patients often results in poor visual outcomes due to the progression of diabetic retinopathy and accelerated development of Diabetic Macular Edema (DME). This study reports on the comparison of the use of intravitreal bevacizumab (BVB, AvastinTM) vs triamcinolone (TA, TriescenceTM) administered at the time of cataract surgery on the final visual and anatomical outcome.

Methods: Prospective randomized trial of intravitreal injection of either 1.25mg of BVB or 2mg of TA at the time of cataract surgery, and at subsequent review if required, in diabetics with visually significant cataract and one of the following:i) refractory DME at the time of surgery,ii) treated DME within the 12 months prior to surgery, or iii) microaneurysms within the foveal avascular zone not amenable to focal macular laser. End points include best-corrected visual acuity (BCVA, LogMAR letters), change in central macular thickness (CMT) on SD-OCT from baseline, number of injections and ocular complications at months 1 and 6 post-operatively.

Results: To date, 24 patients have been recruited at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia, 10 of whom have had surgery (5 in each treatment group). The BVB group were all males, with a mean age of 69±6 years, the TA group had 1 female and a mean age of 67±4 years. At baseline, the BVB group with 59±13 LogMAR letters and CMT of 390±61μm, was similar to the TA group with 55±11 LogMAR letters and CMT of 395±103μm. Five TA and 3 BVB subjects have currently reached the 1-month post-operative time point. Although, in comparison to baseline, the CMT had an improved but not significant trend in the TA group (380±105μm vs. 394±69μm BVB group, p=0.42), the BCVA was found to be significantly better in the BVB group (75±6 letters vs. 59±11 letters TA group, p=0.03). One subject in the BVB group was retreated at this time point. There were no incidences of raised intraocular pressure (≥22mmHg) or any other adverse event recorded in either group.

Conclusions: When administered at the time of cataract surgery in patients with DME, interim results suggest that at 1 month BVB is associated with an improvement in BCVA and TA a reduction in CMT from baseline. Further data regarding longer term outcomes and the need for ongoing retreatment is still pending.

Keywords: 499 diabetic retinopathy • 505 edema • 743 treatment outcomes of cataract surgery