Treatment with statins was associated with a significantly decreased risk of diabetic retinopathy in patients with type 2 diabetes and high cholesterol in a large cohort study from Taiwan.
Statin therapy was also associated with a lower need for invasive treatments for vision-threatening diabetic retinopathy, and the benefits of statin treatment were dose dependent.
While several widely reported studies, including ACCORD-EYE, have suggested that statin treatment slows progression of diabetic retinopathy in patients with diabetes and dyslipidemia, the new study, published online in JAMA Ophthalmology, is among the first to assess statin use for the primary prevention of the eye disorder.
Diabetic retinopathy is a leading microvascular complication of diabetes. According to one estimate, as many as 191 million people worldwide will have developed the vision-threatening eye disorder by 2030.
Yih-Shiou Hwang, MD, PhD, of Chang Gung Memorial Hospital in Taoyuan, Taiwan, and colleagues conducted the population-based cohort study using the National Health Insurance Research Database (NHIRD) of longitudinal claims data from medical practices receiving payment from the single-payer Taiwan National Health Insurance.
Of 1,648,305 patients with type 2 diabetes recorded in the database from 1998 through 2013, a total of 219,359 were eligible for the analysis, including 199,760 patients taking statins and 19,599 not taking statins.
After propensity score matching, the analysis included 18,947 patients in the statin group (10,436 women and 8,511 men; mean [SD] age, 61.5 [10.8]) and 18,947 patients in the nonstatin group (10,430 women and 8,517 men; mean [SD] age, 61.0 [11.0]), with a mean follow-up of 7.6 years for the statin group and 7.3 years for the nonstatin group.
During the study period, 2,004 patients in the statin group (10.6%) and 2,269 in the non-statin group (12.0%) developed diabetic retinopathy.
The analysis also revealed that:
- Patients in the statin group had a significantly lower rate of diabetic retinopathy (hazard ratio [HR], 0.86; 95% CI, 0.81-0.91), nonproliferative diabetic retinopathy (HR, 0.92; 95% CI, 0.86-0.99), and proliferative diabetic retinopathy (HR, 0.64; 95% CI, 0.58-0.70) compared with patients in the nonstatin group
- Patients also had lower rates of vitreous hemorrhage (HR, 0.62; 95% CI, 0.54-0.71), tractional retinal detachment (HR, 0.61; 95% CI, 0.47-0.79), and macular edema (HR, 0.60; 95% CI, 0.46-0.79)
- Compared with the nonstatin group, the statin users had lower rates of interventions such as retinal laser treatment (HR, 0.71; 95% CI, 0.65-0.77), intravitreal injection (HR, 0.74; 95% CI, 0.61-0.89), and vitrectomy (HR, 0.58; 95% CI, 0.48-0.69)
Statin therapy was also associated with lower risks of major adverse cardiovascular events (HR, 0.81; 95% CI, 0.77-0.85), new-onset diabetic neuropathy (HR, 0.85; 95% CI, 0.82-0.89), and new-onset diabetic foot ulcers (HR, 0.73; 95% CI, 0.68-0.78).
“In our study, we found that statin therapy alone was associated with a reduced risk of diabetic retinopathy compared with the nonstatin group (10.6% vs 12.0%),” the researchers wrote. “Our finding could expand the conclusion from the ACCORD-EYE study that the group receiving statins and fenofibrate had the lowest risk of diabetic retinopathy (6.5% in the ACCORD-EYE study) followed by the group receiving statins alone (10.6% in our study and 10.2% in the ACCORD-EYE study).”
“Our study and the ACCORD-EYE study could offer medical strategies to reduce the risk of diabetic retinopathy,” the team added.
Hwang and co-authors noted that statins have been shown to have pleiotropic effects, including improved endothelial function and anti-inflammatory, anti-oxidation, and antithrombotic effects.
In a 2014 study, Raimo Tuuminen and colleagues showed lower intravitreal levels of pro-angiogenic factors, angiopoietin 2, vascular endothelial growth factor, fibrotic factors, matrix metalloproteinase 9, and transforming growth factor β1 in diabetic retinopathy patients treated with a statin versus those who did not receive a statin.
Limitations for the new study, Hwang and colleagues said, included the lack of data on patient serum lipid profiles in the NHIRD database, as well as a lack of data on blood pressure and serum glucose levels.
“Nevertheless, medications for hypertension and glycemic control were matched in the two groups,” the team wrote. “Theoretically, the blood pressure values and serum glucose levels in the two groups were similar.” In addition, since the study was conducted in an Asian population, it is not clear if the findings are applicable to other populations.
Funding for the study was provided by Chang Gung Memorial Hospital in Taoyuan, Taiwan.
The researchers reported having no relevant relationships with industry related to the study.