Abstract
Purpose :
Although diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) are both seen in diabetic retinopathy (DR), it is not clear whether these represent separate clinico-pathological disease processes or whether they are part of the same spectrum of disease. We performed a retrospective cross-sectional study to evaluate the co-existence of PDR and DME in DR patients.
Methods :
Patients with a new diagnosis of PDR were identified who underwent pars plana vitrectomy with endolaser for vitreous hemorrhage. Patients with a new diagnosis of DME (based on clinical examination and thickened central subfield on ocular coherence tomopgraphy, Heidelberg Spectralis ≥320 um in men and ≥305 um in women) were identified who underwent either focal laser photocoagulation or intravitreal anti-VEGF injections. The presence or absence of DME in PDR patients was determined by both clinical examination/grading and OCT measurements within 1-4 weeks of the surgery for a clear assessment of macula. The presence of PDR in DME patients was identified based on presence of new vessels and/or new vitreal hemorrhage. An analysis was done to examine the relationship of DME or PDR with risk factors like type of diabetes, HbA1C levels, mean arterial blood pressure, and LDL levels.
Results :
In the PDR group (134 patients), only 48 patients (35.8%, 95% CI 27.7-43.9%) had DME as defined by increased CRT by OCT, and 21 patients (15.7%, 95% CI 9.5-21.8%) had DME as defined by clinical exam/grading. In the DME group (133 patients), 27 patients (20.3%, 95% CI 13.5-27.1%) had concurrent PDR. Stratification of patients demonstrated that age of the patient, gender, type of diabetes, glycemic control, blood pressure, and LDL were not statistically significant in the development of either DME or PDR.
Conclusions :
The majority of PDR patients (65-85%) have little or no evidence of concurrent DME based on both clinical examination and OCT data. Similarly, the majority of DME patients (80%) have little or no evidence of neovascularization at the same time. Systemic risk factors like blood glucose control, blood pressure control, and lipid control were not significantly associated with the development of DME or PDR in these patients. These findings suggest that PDR and DME represent two distinct disease entities driven by separate molecular mediators and/or genetic factors.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.