The Correlation between Hemoglobin A1c (HbA1c) and Hyperreflective Dots (HRD) in Diabetic Patients

Abstract

Hyperreflective dots (HRD) are activated retinal microglial cells induced by retinal inflammation in diabetic patients. This study was conducted to compare the HRD count of normal and diabetic subjects; to determine the correlation between hemoglobin A1c (HbA1c) levels and HRD count; to determine HbA1c cut-off levels for the appearance of HRD in diabetic patients. A cross-sectional study was conducted among normal and diabetic patients. Fundus photos, SD-OCT images and HbA1c levels were taken. A total of 25 normal subjects, 32 diabetics without retinopathy and 26 mild-to-moderate nonproliferative diabetic retinopathy (NPDR) diabetics were recruited. There was a statistically significant difference between the mean count of HRD among the normal group, the diabetic without retinopathy group and the mild-to-moderate NPRD group. The mean HRD count in the inner retina layer was significantly higher compared to the outer retina layer. There was a significant linear relationship between the HbA1c levels and HRD count. Using the receiver operating curve, the HbA1c level of 5.4% was chosen as the cut-off point for the appearance of HRD. The positive linear correlation between the HbA1c levels and the appearance of HRD may indicate that hyperglycemia could activate retina microglial cells in diabetic patients.

Evaluation of hyper-reflective foci and their association with visual status in diabetic macular edema

“…Our findings are in accordance with the study by Davoudi et al [23], who reported that mean HbA 1c was significantly higher in patients with HF compared to those without HF (8.5 vs. 7.9, p = 0.03); Wong et al [24] found that there was a linear relationship between HbA 1c levels and HF count with a strong, positive correlation (r = 0.952, n = 83, p< 0.05). Vujosevic et al [16] mentioned the rise in HF in diabetics compared to normal individuals and diabetics without clinical retinopathy.…”

Role of hyper-reflective spots in predicting outcomes of intravitreal therapy in diabetic macular edema: A systematic review and meta-analysis

“…The limitations of the studies included in this review are: retrospective design of most of these studies; small sample sizes in most; lack of uniformity in HRS evaluation as an outcome (variable macular areas over which HRS was analyzed, manual versus automated counting, variability in the definition of IR, OR and TR and masking of investigators); short duration of follow up; lack of adjustment for confounders like [blood lipid and sugar levels, 45,46 type of macular edema (CME, DRT, SRD)], lack of uniformity in reporting the statistics and outcomes and significant publication bias.…”

Behavior of hyperreflective spots noted on optical coherence tomography following intravitreal therapy in diabetic macular edema: A systematic review and meta-analysis

“…[ 49 ] showed that the presence of HRS was associated with higher total cholesterol and higher low-density lipoprotein levels. Framme et al ,[ 30 ] Wong et al ,[ 50 ] and De Benedetto et al . [ 18 ] have shown that poor glycometabolic control is associated with more HRS.…”

“…The limitations of the studies included in this review include the following: retrospective designs, inadequate sample sizes, varied HRS measurements (i.e., HRS measured in different macular areas, manual versus automated counting, inconsistent definition of retinal layers), short follow-up duration, lack of adjustment for confounders (blood lipid/sugar levels[ 18 30 49 50 ]), and varying statistical reporting methods and significant publication bias. Also, there has been a lack of uniform definition of HRS in these studies.…”