What factors protect patients with type 2 diabetes from diabetic retinopathy?

This study investigated the risk factors associated with diabetic retinopathy (DR). The authors concluded that factors such as age, total cholesterol, and the presence of other health complications could increase the risk of DR in patients with Type 2 diabetes (T2D).

T2D can lead to a number of other health complications, such as diabetic retinopathy. DR is a chronic complication that affects patients’ eyesight and can lead to blindness. It is caused by damage to the blood vessels found in the tissue of the back of the eye (retina).

Over time, the risk of developing DR increases the longer a patient has T2D. However, not all patients with T2D develop DR. It is not known why some patients develop DR while others do not. The risk factors associated with DR remain under investigation. Whether some factors can also protect against DR is unclear.

This study had 490 patients with T2D. Patients were followed-up for more than 10 years for symptoms of DR. 208 patients (42.5%) developed DR while 282 patients did not. Patients had T2D for an average of 14.7 years.

Overall, 42.5% of patients developed DR. The length of time since diagnosis of T2D was higher in patients with DR (15.23 years) than no DR (14.25 years). 

HbA1c levels (average blood glucose over the past 3 months) were higher in patients with DR (9.03%) than no DR (8.58%). Bilirubin, a measure of liver health, was lower in patients with DR (7.58 μmol/L) than no DR (8.96 μmol/L). Total cholesterol levels were higher in patients with DR (4.82 mmol/L) than no DR (4.55 mmol/L). High ApoB levels, which are linked to heart disease, were higher in patients with DR (0.93 g/L) than no DR (0.85 g/L). 

Diabetic kidney disease was more common in patients with DR (52.4%) than no DR (19.86%). Diabetic nerve problems were also more common in patients with DR (59.62%) than no DR (40.07%).

Certain factors increased the risk of developing DR. These included high ApoB levels (30.647-fold), kidney disease (3.176-fold), and nerve problems (1.864-fold).

Certain factors were protective against DR. These included high bilirubin levels (5.7% lower risk) and lower total cholesterol levels (29.6% lower risk).

The authors concluded that kidney disease, nerve problems, and high ApoB levels were associated with a higher risk of DR. However, high bilirubin and low total cholesterol levels may help protect against DR.

This study had a small number of patients. Larger studies are needed to confirm these results.

Talk to your doctor about ways to help lower your risk of developing diabetic retinopathy.