Findings from a recent study published in Ophthalmic Research evaluated the correlation between fundus blood flow parameters and the severity of pathological biopsy in patients with diabetic kidney disease (DKD).
Give me some background.
DKD is a serious microvascular complication of diabetes mellitus with early symptoms that can be difficult to detect.
Typically: Progression to end-stage renal disease requires dialysis or kidney transplantation to maintain life.
- Meaning: Early diagnosis is crucial for improving prognosis and quality of life
Go on …
While renal biopsy is considered the gold standard for diagnosing DKD, using it as a routine examination can be difficult due to its invasive nature.
And despite previous studies comparing optical coherence tomography angiography (OCT-A) findings with renal dysfunction, their relationship with DKD pathological biopsies remains unknown.
Now talk about the study.
In this retrospective study, investigators collected the data of 157 eyes from 157 patients with type 2 diabetes mellitus who completed renal pathology biopsies and OCT-A examinations, including:
- Renal function
- 24-hour urine protein quantification
- Macular flow imaging
DKD pathology biopsies were graded as stages 1-4, and differences and correlations of the parameters were compared between groups.
Findings?
The urinary microalbumin to urinary creatinine ratio (mALB/NCR) increased with pathological grading, while the glomerular filtration rate decreased (p < 0.01).
There was a corresponding decrease in retinal blood flow in superficial, deep, and full paracentral rings, which correlated with increased DKD pathological grading (p < 0.01).
- Note: The highest blood flow density was in the whole layer (r2 = -0.707).
Anything else?
In the early DKD model, three parameters were statistically significant, including:
- Whole-layer blood flow density
- mALB/NCR
- Diabetes duration
Expert opinion?
“The entire retina has a good discriminatory ability between the early and late stages of DKD pathology and may be an important reference index to assist or reduce the number of renal pathological biopsies in patients with diabetes mellitus,” the study authors noted.
Limitations?
These included:
- Renal pathological biopsies were judged via optical microscopy, though more detailed pathological changes require further analysis with electron microscopy
- The DKD model was not externally validated due to the sample size
Take home.
These findings suggest that a decrease in macular retinal blood flow density measured by OCT-A was closely associated with an increase in pathological grading of DKD.
Consequently: OCT-A could be used as a noninvasive parameter for monitoring early changes in DKD.