Assessment of real-life visual outcomes and treatment efficacy of diabetic macular edema in patients with type 2 diabetes

BACKGROUND: Diabetic macular edema (DME) is a major cause of vision loss in individuals with diabetes. This study evaluated the long-term visual prognosis of patients with type 2 diabetes (T2D) by assessing real-world DME treatment outcomes. METHODS: Patients with T2D and DME at Oulu University Hospital during 2010-2023 were included. The effect of DME intervention (anti-VEGF-agents, macular laser or both, intravitreal corticosteroids, observation) was evaluated by changes in visual acuity (VA) and residual edema. The dataset comprised additional variables, including age, sex, age at T2D diagnosis, timing of onset for diabetic retinopathy (DR) and DME, DR severity, glucose levels, other comorbidities, occurrences of treatment interruption, and adverse effects related to intravitreal therapy. RESULTS: Of 549 screened patients with T2D, 1145 DME episodes in 355 patients (560 eyes) were included. Mean ages at T2D, DR, and DME diagnosis were 51.0, 61.7, and 66.4 years, respectively. Mean HbA1c at DME treatment initiation was 64.3 mmol/mol; 93.0% had hypertension medication and 47.6% had diabetic nephropathy. DME was most treated with anti-VEGF injections alone (55.3%) or combined with laser (20.4%), yielding mean VA improvements of 3.8 [3.0-4.6] and 3.6 [2.5-4.6] ETDRS letters (both p < 0.001), respectively. Intravitreal corticosteroids (3.1%) resulted in a gain of 4.3 [1.2-7.4] letters (p = 0.014), whereas macular laser alone (12.8%) and observation (8.3%) showed no significant effect. Residual edema occurred in 38.1% (anti-VEGF), 43.2% (combination), 54.7% (observation), and 80.6% (corticosteroid) of cases. Adverse events related to any DME treatment were rare. CONCLUSIONS: Despite recurrent episodes of DME, most patients with T2D experienced improvement in visual acuity. Anti-VEGF agents alone or combined with macular laser appeared to be beneficial in terms of both visual gain and reduction of edema.