Efficacy of anti-VEGF monotherapy versus anti-VEGF therapy with subthreshold micropulse laser (SML) in the management of diabetic macular oedema (DMO): a systematic review and meta-analysis

Background: Intravitreal injection anti-vascular endothelial growth factor (IVI anti-VEGF) therapy serves as the primary treatment for centre involving diabetic macular oedema (DMO). Conventional laser therapy (CLT) adjunct has proven beneficial; however, it is not widely used due to significant risks of retinal scarring. Subthreshold micropulse laser (SML) therapy has, however, emerged as a comparable alternative to combination therapy, offering a distinct advantage by mitigating the risk of retinal scarring. Methods: A search of six databases was conducted. A meta-analysis of mean differences was performed including subgroup analyses where appropriate. Primary outcome was the number of injections at 12-14 months; secondary outcomes were changes in central macular thickness (CMT) and best corrected visual acuity (BCVA) at 6-8 months and 12-14 months. Results: A total of ten papers including six randomised clinical trials and four retrospective clinical studies were included in our study, capturing 563 eyes of 478 patients. Overall, the risk of bias was moderate for these studies. Significantly fewer anti-VEGF therapy injections were administered in the combination therapy versus anti-VEGF monotherapy patients at 12-14 months who had poor visual acuity (6/18 Snellen or worse) at baseline, mean difference - 2.25 (95% CI; - 3.35, - 1.15; p < 0.05). Combination therapy was not associated with significantly fewer intravitreal injections in patients with a higher visual acuity (6/15 Snellen or better) at baseline. Our analysis also showed significant improvements to both BCVA and CMT were reached at 6 - 8 month post-baseline at the 95% confidence intervals: - 1.13 (- 2.09, - 0.16) and - 4.04 (- 7.59, - 0.50). These improvements remained statistically significant at 12-14 months: - 0.94 (- 1.67, - 0.20) and - 1.92 (- 3.52, - 0.32) respectively with combination therapy. Conclusion: Our findings demonstrate that combination therapy (SML + IVI anti-VEGF) is associated with fewer intravitreal injections. We report a better BCVA and a reduction in CMT at 6 and 12 months from baseline with combination treatment compared to the IVI anti-VEGF monotherapy comparator. SML is a proven non-scarring cost-effective therapy for DMO that should be readily available in the medical retinal therapy as it may reduce the burden of care.