Hyperglycemia Biggest Risk Factor in Retinopathy

The dominant risk factor for retinopathy was confirmed to be hyperglycemia in a study published in JAMA Ophthalmology,¹ which also confirmed that hypertension, obesity, and overweight remained as comorbidities to manage to reduce the overall risk.

Visual impairment and blindness are commonly caused by diabetic retinopathy (DR), which affects about 20% of young individuals with type 1 diabetes (T1D). Although glucose control is the foremost method of reducing the risk of DR in general,² risk estimates have become less reliable as treatments for DR have changed. This study aimed to ascertain what risk factors can lead to the development of DR and their importance when compared with hemoglobin A_1C (HbA_1C) in patients with T1D.

The Swedish National Diabetes Register was used to conduct the study and collect data on patients. The cohort consisted of had T1D for less than 5 years enrolled between January 1, 1998, and December 31, 2017. Participants needed at least 4 visits during a follow-up period of 8 years with data attached to all visits. Follow-up times were separated into groups based on length of time: 8 to 9 years, 10 to 11 years, 12 to 13 years, 14 to 15 years, and 16 to 20 years. Incidence of retinopathy was recorded for each participant.

Controlling blood glucose level is the best method of preventing retinopathy in patients with T1D | Image credit: NanSan - stock.adobe.com

There were 9358 participants who were included in the study, where the mean (SD) age at the first visit was 14 (8) years and 44% were women. The mean follow-up was 11 (3) years and duration of diabetes at first registration was 1.2 (1.6) years. A total of 33% of the participants had retinopathy.

The strongest risk factor of retinopathy was the mean HbA_1C level per 1 SD increase (adjusted OR [aOR], 1.81; 95% CI, 1.73-1.89). Mean systolic blood pressure (aOR, 1.24; 95% CI, 1.19-1.30), mean diastolic blood pressure (aOR, 1.27; 95% CI, 1.21-1.33), smoking (aOR, 1.20; 95% CI, 1.15-1.25), and mean body mass index (aOR, 1.30; 95% CI, 1.24-1.37) were all risk factors of any retinopathy with risk increasing with increased levels of the risk factor. A reduced risk of retinopathy was associated with increased high-density lipoprotein cholesterol (aOR, 0.87; 95% CI, 0.82-0.92). Higher HbA_1C level was associated with preproliferative retinopathy or worse (aOR, 2.63; 95% CI, 2.35-2.95) but no other risk factors were statistically significant.

There were some limitations to this study. Some data, such as abdominal fat measurements and continuous glucose monitoring, were not available for evaluation. The follow-up was also over a longer period of time at 11 years.

“This study confirms hyperglycemia as the dominant risk factor for retinopathy but also highlights that overweight, obesity, and hypertension need to be managed not only for cardiovascular diseases but also to potentially reduce the risk of retinopathy,” the authors concluded.

References

1. Ahmadi SS, Ludvigsson J, Imberg H, Nyström T, Lind M. Risk factors for retinopathy in young adults with type 1 diabetes. JAMA Ophthalmol. Published online December 12, 2024. doi:10.1001/jamaophthalmol.2024.5274
2. Prevention: diabetic retinopathy. NHS. Updated December 16, 2024. Accessed December 16, 2024. https://www.nhs.uk/conditions/diabetic-retinopathy/prevention/