Lipid-lowering drugs, lower DR risk may go hand in hand

A large retrospective cohort study found that patients with type 2 diabetes benefitted from lipid-lowering medications, in that those drugs seem to be associated with lower incidences rates of nonproliferative diabetic retinopathy (NPDR), PDR, and diabetic macular edema (DME).

The study also reported “modest evidence” that the patients were less likely to undergo treatment with intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs, laser, or vitrectomy.

The negative effects of diabetes cannot be overemphasized, and the disease has been observed to be increasing steadily among U.S. adults, with more than 40% of the population is diabetic or pre-diabetic.

However, children and adolescents also are being adversely affected, with the disease having increased by an estimated 7% annually in younger individuals from 2002 to 2012, according to the authors of a recent report in the American Journal of Ophthalmology (2019; doi: https://doi.org/10.1016/j.ajo.2019.05.029). The authors are from the Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA and All Eyes Consulting, LLC, New York.

In addition to diabetes, other identified risk factors for DR are hypertension, smoking, high blood glucose values, and dyslipidemia.

Initially, in 2007, there was not enough evidence in a systematic review to advocate lipid-lowering drugs to prevent DR, but since then interest has been mounting in the association between dyslipidemia, lipid-lowering drugs, and ocular diseases associated with diabetes.

The data that have been emerging worldwide on the relationship between lipid-lowering medications and DR led Daniel Vail and colleagues to perform a retrospective cohort analysis of a database of commercial insurance claims in the United States that encompassed a diverse population of patients, with the goal of evaluating the effect of lipid-lowering medications on DR and diabetic complications that required intervention in that population.

The main study outcomes were any signs of DR, as measured by diagnostic codes for NPDR, PDR, DME, and procedural codes for treatments for retinopathy in the patient records, such as anti-VEGF injections, laser, and vitrectomy, the investigators explained. They noted that the exposure of interest in this study was use of lipid-lowering drugs before and after the patients were diagnosed with diabetes.

Their findings

The study included 269,753 patients with type 2 diabetes who were covered by commercial insurance from 2008 to 2015.

The investigators found that there were 99,233 (37%) of these who were taking lipid-lowering drugs, and about 6% of them had a diagnostic code for NPDR, PDR, or DME or they had a procedural code for intravitreal injections, pars plana vitrectomy, or laser after they had been diagnosed with diabetes compared with 6.5% of patient who were not taking lipid-lowering medications (p < 0.01).

The authors reported further that adjusted time-to-event analyses showed that patients who took lipid-lowering medications before being diagnosed with type 2 diabetes were both less likely to progress to any retinopathy diagnosis (hazard ratio [HR], 0.60, 95% confidence interval [CI], 0.55-0.65) and less likely to receive any treatment for retinopathy (HR, 0.81, 95% CI, 0.78-0.84).

They pointed out that these findings were significant both at the aggregate level and at the individual diagnostic level (NPDR: HR, 0.63, 95% CI 0.57-0.69; PDR: HR, 0.45, 95% CI 0.37-0.54; and DME: HR, 0.39, 95% CI, 0.33-0.45) and at each treatment category level (anti-VEGF injection: HR, 0.81, 95% CI, 0.78-0.84; laser: HR, 0.62, 95% CI, 0.47-0.81; and vitrectomy: HR, 0.71, 95% CI, 0.59-0.85).

The authors commented that they found consistent evidence that patients who were taking lipid-lowering medications were less likely to develop NPDR, PDR, or DME, and modest evidence that these patients were less likely to receive intravitreal injections of anti-VEGF medication, laser treatments, or vitrectomy.

The current findings agree with the analyses of two large Japanese and Taiwanese claims databases, which have relatively homogeneous populations.

This agreement is important, the investigators pointed out, “as patients in the United States may have different risk profiles for ophthalmic disease in the setting of diabetes, and commercially insured patients in the United States who are diagnosed with [DR] may face different treatment pathways than patients in Taiwan or Japan, countries with very different health systems.”

They concluded: “Our findings have implications for the management of a common condition with significant ophthalmic morbidities and health systems costs. At the level of the individual provider, our findings support the use of lipid-lowering medications in diabetic patients with hyperlipidemia, as these medications may have visual benefits beyond their systemic indications. Further research is needed to conclusively confirm the role of lipid-lowering medications in the prevention of [DR] and to estimate the consequences that these medications may have for ophthalmic use.”

The study was supported by the Heed Ophthalmic Foundation.