Predictive factors of better outcomes by monotherapy of an antivascular endothelial growth factor drug, ranibizumab, for diabetic macular edema in clinical practice

Intravitreal ranibizumab (IVR) has been approved for treating diabetic macular edema (DME), and is used in daily clinical practice. However, the treatment efficacies of IVR monotherapy in real-world clinical settings are not well known. The medical records of 56 eyes from 38 patients who received their first IVR for DME between April 2014 and March 2015, and were retreated with IVR monotherapy as needed with no rescue treatment, such as laser photocoagulation, were retrospectively reviewed. The clinical course, best-corrected visual acuity (BCVA), and fundus findings at baseline, before the initial IVR injection, and at 12 months, were evaluated. Twenty-five eyes from 25 patients (16 men; mean age 68.7±9.8 years) who received IVR in the first eye, or unilaterally, without any other treatments during follow-up were included. After 12 months, mean central retinal thickness (CRT), which includes edema, was reduced (P=.003), although mean BCVA remained unchanged. There was a negative correlation between individual changes in BCVA (r=-.57; P=.003) and CRT (r=-.60; P=.002) at 12 months compared with baseline values. BCVA changes were greater in individuals with a history of pan-retinal photocoagulation at baseline (P=.026). After adjusting for age and sex, CRT improvement >100mm at 12 months was associated with a greater CRT at baseline (OR 0.87 per 10mm [95% CI 0.72-0.97]; P=.018) according to logistic regression analyses; however, better BCVA and CRT at 12 months were associated with a better BCVA (r=0.77; P<.001) and lower CRT (r=0.41; P=.039) at baseline, respectively, according to linear regression analyses. IVR monotherapy suppressed DME, and the effects varied according to baseline conditions. Eyes that had poorer BCVA or greater CRT, or a history of pan-retinal photocoagulation at baseline, demonstrated greater improvement with IVR monotherapy. In contrast, to achieve better outcome values, DME eyes should be treated before the BCVA and CRT deteriorate. These findings advance our understanding of the optimal use of IVR for DME in daily clinical practice, although further study is warranted.