Baseline characteristics and treatment response to macular laser in people with diabetic macular edema (DME) and central retinal thickness (CRT) of <400μm in the DIAMONDS trial.

Abstract

Purpose : DIAMONDS was a randomized, double-masked, non-inferiority clinical trial including 266 participants with <400µm CRT DME. DIAMONDS found subthreshold micropulse laser to be not only non-inferior but also equivalent (equivalence margin +/- 5 ETDRS letters) to standard macular laser. Herein, we sought to determine whether baseline characteristics of participants could predict outcomes at month 24.

Methods : Potential associations between baseline participant characteristics, including age, sex, HbA1c, duration of DME, best corrected visual acuity (BCVA), CRT, macular volume and previous treatment with macular laser or anti-VEGFs, and outcomes, including BCVA at month 24, change in BCVA and loss of 5 or more and 10 or more ETDRS letters from baseline to month 24, requirement of rescue treatment (anti-VEGF) and number of anti-VEGF needed. Exploratory linear, logistic and Poisson regression models were used to look for possible associations between selected baseline variables and outcomes.

Results : In a multiple regression model, age, sex, duration of DME, HbA1c, baseline BCVA, CRT, macular volume, previous treatment with macular laser and/or anti-VEGFs statistically significantly predicted BCVA at month 24 [F(9, 218) = 16.73; P<0.0005, R² = 0.409]. Baseline BCVA and HbA1c added statistically significantly to the prediction (p<0.05), although the effect did not appear to be of clinical relevance.

In a binomial logistic regression model sex statistically significantly predicted requirement for anti-VEGFs (OR 1.9 [for females], p=0.04) but the effect did not appear to be of clinical relevance. In a Poisson regression model baseline BCVA (p<0.001), age (p=0.027), HbA1c (p=0.008), duration of DME (p<0.001) and sex (p=0.003) statistically significantly predicted number of anti-VEGF injections, but, once again, the effect did not appear to be of clinical relevance.

There were no statistically significant associations found between baseline characteristics and change in BCVA and loss of 5 and 10 or more ETDRS from baseline to month 24.

Conclusions : Baseline characteristics of participants in DIAMONDS appeared to have little impact on the response to macular laser treatment which, thus, should be offered to all patients fulfilling DIAMONDS eligibility criteria.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.