This major observational study suggests that statins reduce the risk of diabetic neuropathy, diabetic foot ulcers, and more importantly the risk of diabetic retinopathy. Risk reduction ranges from 10% to 45%. This could be due to statin-induced decreased microvascular inflammation. About 38,000 patients were followed for 7.5 years.

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Observational

January 2019

Importance

Diabetic retinopathy is the leading cause of blindness in working-age adults. Studies have suggested that statins may reduce the risk of developing diabetic retinopathy.

Objective

To investigate the association between statin therapy and the development of diabetic retinopathy in patients with diabetes and dyslipidemia.

Design

This population-based cohort study, conducted among 37,894 Taiwanese patients between January 1, 1998, and December 31, 2013, used the National Health Insurance Research Database to identify patients with type 2 diabetes and dyslipidemia.

Outcomes were compared between those taking statins and those not taking statins. Statistical analysis was performed from May 1 to 31, 2018.

Exposure

Statin therapy with a statin possession rate of 80% or more with no other lipid-lowering medications.

Outcomes

Any stage of diabetic retinopathy and treatments for vision-threatening diabetic retinopathy.

Results

Of 1,648,305 patients with type 2 diabetes, 219,359 were eligible for analysis over the study period, including 199,760 patients taking statins and 19,599 patients not taking statins.

After propensity score matching, there were 18,947 patients in the statin group (10 436 women and 8511 men; mean age, 61.5 years) and 18,947 patients in the nonstatin group (10,430 women and 8,517 men; mean age, 61.0 years), with a mean follow-up of 7.6 years for the statin group and 7.3 years for the non-statin group.

During the study period, 2004 patients in the statin group (10.6%) and 2269 patients in the nonstatin group (12.0%) developed diabetic retinopathy.

Compared to non-statin users, patients in the statin group had a significantly lower rates of (p<0.05):

Diabetic retinopathy (HR 0.86)
Nonproliferative diabetic retinopathy (HR 0.92)
Proliferative diabetic retinopathy (HR 0.64)
Vitreous hemorrhage (HR 0.62)
Tractional retinal detachment (HR 0.61)
Macular edema (HR 0.60)
Retinal laser treatment (HR 0.71)
Intravitreal injection (HR 0.74)
Vitrectomy (HR 0.86)
Retinal lasers (RR 0.61)
Intravitreal injections (RR 0.68)
Vitrectomies (RR 0.54)
Major adverse cardiovascular events (HR, 0.81)
New-onset diabetic neuropathy (HR, 0.85)
New-onset diabetic foot ulcers (HR, 0.73)

Conclusions

Statin therapy was associated with a decreased risk of diabetic retinopathy and need for treatments for vision-threatening diabetic retinopathy in Taiwanese patients with type 2 diabetes and dyslipidemia.