Sub-tenon triamcinolone acetonide injections in diabetic macular edema: analyzing interstitial fluid glucose fluctuations with continuous monitoring technology

This study was aimed to determine whether sub-tenon triamcinolone acetonide (STTA) injections influence interstitial fluid (ISF) glucose fluctuations in patients with diabetic macular edema (DME) and assess whether age affects the glycemic response. This prospective study included 18 patients with DME receiving STTA injections. ISF glucose was monitored using a continuous glucose monitoring system. Glucose data were evaluated over a 7-day period before and after STTA injection. Time in range (TIR), time above range (TAR), and time below range (TBR) were recorded before and after STTA injection; differences before and after injection were calculated and compared by age (< 70 vs. ≥ 70 years). Results showed a non-significant trend toward an increase in average ISF glucose (from 156.3 ± 55.4 mg/dL to 163.5 ± 50.6 mg/dL; p = 0.055). TAR rose from 28.0% to 33.3% (p < 0.05), whereas TBR decreased from 3.42% to 0.9% (p < 0.05); TIR remained unchanged. ΔISF glucose was 15.8 ± 11.3 mg/dL and 1.5 ± 13.2 mg/dL in those aged ≥ 70 and < 70 years, respectively (p = 0.08). Patients aged ≥ 70 years showed increased ΔTAR (12.0% vs. 0.8%) and reduced ΔTBR (-4.8% vs. - 0.9%) (p < 0.05). STTA injections may increase TAR, especially in older patients, highlighting the need for close glucose monitoring.