Outcomes in clinical studies can differ from real-world results, often because patient compliance and adherence factor more meaningfully. Researchers of the Predicting Optimal Cancer Rehabilitation and Supportive care (POLARIS) study believe their work provides an important overview of the 12‐month outcomes for patients with diabetic macular edema (DME) treated with ranibizumab under real‐world settings. Participants in the study came from eight different European countries: France, Germany, Greece, Portugal, Russia, Slovakia, Spain and the United Kingdom.

POLARIS analyzed the outcomes of two groups: all treated patients (804 patients) and first-year completers, i.e., those who had a visual acuity (VA) assessment at 12 months; 568 patients. The mean baseline VA score was 59.4 letters and the mean change in VA was 4.4 letters after 12 months. Although patients attended approximately 10 visits over the year, only 58% of these were treatment visits. The mean number of injections was 4.9. Measuring central retinal thickness, the mean at baseline was 410.6μm, and the mean change was –115.2μm after one year.

While other observational studies showed similar VA gains, the same is not true of in the active phases of randomized studies. The RESTORE and RETAIN studies recorded a mean change in VA at 12 months of roughly six letters with ranibizumab as-needed or treat-and-extend, and the RISE/RIDE study reported a gain of approximately 12 letters with monthly dosing. Even when RISE/RIDE patients switched to as-needed ranibizumab treatment, they had an average of 4.5 injections and maintained 12 letters of gain.  

The researchers noted in their paper that potential reasons for differences in VA outcomes achieved in real‐world studies compared with those achieved in clinical studies may relate to the fact that observational studies rely on whatever method the clinic uses, whereas randomized studies use best‐corrected VA measurements. Also, dosing in real‐world studies may be reactive, and achievement of short‐term gains may result in reduction of future injections despite the possibility of further improvement.

Since data collection for the POLARIS study, the recommended ranibizumab regimen changed in Europe from as-needed with monthly monitoring to a more flexible approach guided by the physician. The authors believe that future studies must determine the impact of this change on treatment practice.