A new study published in Retina assessed the characteristics and associated factors of retinal microvasculopathy and neurodegeneration in insulin therapies prescribed to children with type 1 diabetes mellitus (T1DM) who did not have concomitant diabetic retinopathy (DR) via optical coherence tomography (OCT) and OCT angiography (OCTA).
Give me some background first.
DR is the most common ocular complication of T1DM and can cause severe visual impairment.
Multiple daily insulin injections (MDI) and continuous subcutaneous insulin infusion (CSII) are two approaches to daily insulin therapies.
Prior results from randomized clinical trials (RCTs) have demonstrated that CSII achieves better metabolic control and decreased complications in children with T1DM compared to MDI.
How does that connect to study?
There is a dearth of studies that have measured whether MDI or CSII impacts microvascular and neurodegenerative changes in T1DM children without DR.
Consequently, a research team sought to understand if CSII or MDI exacerbates microvascular and neurodegenerative changes to provide evidence for DR monitoring protocols in T1DM pediatric patients.
Now, talk about the study.
In this cross-sectional observational study, investigators enrolled 41 T1DM children with multiple daily insulin injections (MDI), 22 T1DM children with continuous subcutaneous insulin infusion (CSII), and 62 age-matched normal controls.
They used the SPECTRALIS optical coherence tomography (OCT) machine to scan a 6x6 mm square area of the posterior retina.
Findings?
Of note, the following were all significantly lower than those in the T1DM-CSII and control groups:
- Vessel density (VD) of the superficial vascular plexus (SVP)
- Intermediate capillary plexus (ICP)
- Deep capillary plexus (DCP)
In the T1DM-MDI cohort, researchers observed that higher Hemoglobin A1c (HbA1c) was associated with lower VD of SVP (p=0.015).
Tell me more.
Also, the foveal avascular zone morphology index (FAZM) in the T1DM-MDI and T1DM-CSII groups was smaller than the control group (p=0.040).
Investigators reported no statistically significant difference in the thickness of the retina between the three groups (p>0.05).
Expert opinion?
According to the study authors, “These results suggested that reduction of blood flow and impairment of the blood-retina barrier have occurred due to chronic hyperglycemia before apparent signal of DR in T1DM children.”
They also highlighted that “compared to MDI therapy, CSII therapy may be protective against retinal microvascular damage in early DR stages.”
Limitations?
As a single-center study, the analysis included a relatively small number of participants, especially in the T1DM-CSII group.
Additionally, the cross-sectional design did not feature long-term retinal data to track T1DM retinal changes in different DM stages.
Lastly, the study didn’t collect data on microRNAs (miRNAs) or hypoglycemia, which could confirm the protective mechanism of CSII on retinal microvasculopathy.
Take home.
The VD of the posterior retina was significantly lower in T1DM children treated with MDI than healthy controls and was associated with higher HbA1c levels.
Further, researchers reported a notable difference in VD between the T1DM-MDI and T1DM-CSII groups with similar HbA1c.
Meaning…
These findings suggest that OCTA may be advantageous to utilize in the detection of retinal abnormalities in early T1DM children.
Finally, CSII could be a better option for children with T1DM to prevent the retinal complications associated with MDI.