Intensive glucose control can offset poor lipid profile to slow diabetic retinopathy progression
In patients with type 2 diabetes, intensive glucose control appears to interact with lipid levels in relation to the progression of diabetic retinopathy, according to recent findings.
Nasrin Azad, MD, of the endocrinology section at Edward Hines Jr. VA Hospital in Hines, Illinois, and colleagues evaluated data from 858 patients enrolled in the Veterans Affairs Diabetes Trial. Participants had type 2 diabetes insufficiently controlled with maximum doses of oral antidiabetes agents or insulin therapy and had available seven-field stereo fundus photographs at baseline and 5 years.
Participants were assigned to undergo treatment with intensive glucose control (intervention group) or standard glucose control (control group). The researchers assessed the onset and progression incidence rates of diabetic retinopathy, and they evaluated these outcomes in terms of biologically relevant variables, including age, HbA1c, diabetes duration, blood pressure, estimated glomerular filtration rate, fibrinogen, plasminogen activator inhibitor type 1, C-peptide and history of ocular disorders. Measurements were assessed only in relation to progression of diabetic retinopathy, and baseline lipid measurement were assessed as continuous variable.
Of the 858 participants with complete data available, 595 had baseline retinopathy (305 in the intervention group and 290 in the control group). Researchers found that of the participants with baseline retinopathy, 120 (54 in the intervention group, 66 in the control group) had progression to diabetic retinopathy during the study period. Thirty-one percent of participants with baseline retinopathy had only microaneurysms, 37% had mild nonproliferative diabetic retinopathy, 23% had moderate to severe proliferative diabetic retinopathy and 9% had proliferative diabetic retinopathy.
Researchers found an interaction between glycemic treatment assignment and baseline lipid parameters. In models that included this interaction, the odds of diabetic retinopathy progression were 44% lower in the intervention group with baseline total cholesterol of at least 200 mg/dL compared with the control group (P = .007). Participants in the intervention group with baseline LDL of at least 120 mg/dL had 37% decreased odds of diabetic retinopathy progression (P < .02). The intervention group with HDL of at least 40 mg/dL had 37% lower odds of diabetic retinopathy (P < .007).
In the fifth year of the study, the researchers found that reduction of total cholesterol by at least 40 mg/dL lowered the odds of diabetic retinopathy progression by 47% (P < .0001). Reduction of LDL by at least 40 mg/dL (P < .004) at the fifth year was associated with 44% lower odds of diabetic retinopathy progression, and a decrease in triglycerides by at least 60 mg/dL was associated with 38% lower odds (P = .004).
Increases in total cholesterol by at least 20 mg/dL were associated with 80% increased odds of diabetic retinopathy progression (P < .0001), and increases in LDL by at least 60 mg/dL were associated with 180% increased odds of progression (P < .004). Adjustment for covariates found that those with lower total cholesterol in the fifth year and higher HDL throughout the study had significantly reduced diabetic retinopathy progression in the intervention group.
“Our data show interesting interactions between [intensive glucose control] and various lipid parameters in relationship to [diabetic retinopathy] progression,” the researchers wrote. “Patients assigned to the [intensive glucose control] arm with higher baseline levels of [total cholesterol] and LDL-[cholesterol] or higher HDL-[cholesterol] benefited the most and demonstrated lower odds of progression of [diabetic retinopathy]. Those assigned to the [intensive glucose control] arm with decreased levels of [total cholesterol], [triglycerides] or LDL-[cholesterol] by the end of the study also had smaller odds of [diabetic retinopathy] progression. Higher HDL-[cholesterol] was associated with better response to [intensive glucose control] throughout the study.” – by Jennifer Byrne
Disclosure: The researchers report no relevant financial disclosures.