Short-term poor glycaemic control linked to retinal microvascular changes in paediatric T1D
A short period of poor glycaemic control may be associated with retinal microvascular changes in children with type 1 diabetes (T1D), according to a small study from Singapore.
“We found that short-term poor glycaemic control was associated with suboptimal retinal microvascular morphology including wider retinal arteriolar calibre and larger retinal arteriolar branching angle,” said the researchers.
“Such morphological abnormalities may indicate a worse hypoxia-induced formation and a lower complexity of less than ideal oxygenation caused by chronic hyperglycaemia,” they said, suggesting that this may point to further development of microvascular complications among paediatric patients with poor glycaemic control.
This retrospective longitudinal study comprised 55 children aged 10–16 years with T1D from the KK Women’s and Children’s Hospital, Singapore. Of these, 28 children with poor glycaemic control (average HbA1c ≥8 percent over the year) were matched with 27 children with good glycaemic control (HbA1c <8 percent over the year).
HbA1c was determined by blood tests conducted at each three-monthly visit to the diabetes clinic, while retinal photography was conducted at the final end-of-year clinic visit. All patients were on insulin replacement treatment and were followed up for 1 year.
Patients with poor glycaemic control had wider retinal arteriolar calibre (139.84 vs 133.81 µm; p=0.03) and larger retinal arteriolar branching angle (85.8 vs 78.3 degrees; p=0.04) compared with patients with good glycaemic control. [BMC Ophthalmol 2017;17:60]
After adjusting for ethnicity, body mass index, T1D duration, and low-density lipoprotein cholesterol, one year of poor glycaemic control was associated with abnormal retinal microvascular findings, namely wider retinal arteriolar calibre (6.0 µm, 95 percent confidence interval [CI], -0.9 to 12.8) and larger retinal arteriolar branching angle (10.1 degrees, 95 percent CI, 1.4–18.9) compared with patients with good glycaemic control.
There was no significant difference between patients with good and poor glycaemic control in terms of other retinal morphology measures examined in this study (ie, retinal arteriolar tortuosity, fractal dimension, and retinal venular parameters).
“[C]hanges in retinal vascular geometry have been extensively studied and validated as proxies for small-vessel dysfunction, particularly in diabetes and other microvascular disorders,” said the researchers.
They cautioned that the small sample size may have limited the generalizability of the findings to the entire paediatric T1D population in Singapore, as well as affected the identification of the association between poor glycaemic control and other retinal microvascular parameters. They called for larger studies with a more extensive follow-up period to further establish the findings.