Serum pro-inflammatory factors as predictors of persistent diabetic macular oedema with limited anatomic response to anti-VEGF: association with intravitreal injection treatment profiles in real-world setting.

PURPOSE

To study the role of serum levels of pro-inflammatory factors in the identification of persistent diabetic macular oedema (DME) cases with limited anatomic response to anti-VEGF. Additionally, possible predictive associations between serum factors and intravitreal treatment profiles were analysed.

METHODS

Cases with DME were treated with monthly bevacizumab (BVZ). After the sixth month of follow-up, if the change in central foveal thickness (CFT) was <20% of baseline, combination treatment with triamcinolone was initiated. All cases underwent a baseline laboratory workup including inflammatory, metabolic and prothrombotic factors. The following outcome parameters were evaluated: percentage of CFT change from baseline, occurrence of persistent DME with <20% change in CFT, achieving CFT <330 μm with ≤6 BVZ injections, total number of intravitreal injections (IVI), number of IVI after the 6th month and number of triamcinolone acetonide (TCA) injections.

RESULTS

A total of 58 cases were included receiving a mean of 7.23 ± 1.55 IVI in 12 months, resulting in a significant improvement of visual acuity (VA) and CFT. No significant differences were found for baseline CFT, baseline LogMAR VA, diabetic retinopathy grade, age or duration of DM2 between cases initiating TCA and those treated only with anti-VEGF. Significant correlations were found between total number of IVI and the following serum factors: high-sensitivity C-reactive protein (hsCRP) (p = 0.004, r = 0.395), creatinine (p = 0.023, r = 0.338) and homocysteine (p = 0.037, r = 0.309). Regression analysis revealed that hsCRP was a significant predictor of TCA treatment (p = 0.028, r  = 0.350). Cases requiring ≤6 IVI had significantly lower values of hsCRP (1.33 ± 1.07 versus 2.46 ± 2.18 mg/l, p = 0.016) and creatinine (0.71 ± 0.28 versus 0.94 ± 0.19 mg/dl, p = 0.003).

CONCLUSIONS

Serum markers of microvascular damage (hsCRP, homocysteine and creatinine) were associated with a higher frequency of IVI due to persistent DME, suggesting a role for such biomarkers in the identification of limited responders to anti-VEGF monotherapy.