Is the use of sodium-glucose cotransporter 2 inhibitors related to the occurrence of eye diseases in patients with type 2 diabetes?

This study investigated the link between sodium-glucose cotransporter 2 inhibitors (SGLT2is) and eye (ocular) diseases in patients with type 2 diabetes (T2D). The data showed that there was no link between the occurrence of eye diseases and SGLT2is in these patients. Some SGLT2is such as ertugliflozin (Steglatro) and empagliflozin (Jardiance) may protect against eye disease while canagliflozin (Invokana) may promote eye disease. 

T2D is a chronic disease that results in high blood glucose levels. Eye diseases related to long-term, uncontrolled high blood glucose include cataracts (cloudy eye lens with blurry vision), glaucoma (optic nerve damage often due to high pressure), diabetic retinopathy (damaged blood vessels of light-sensitive tissues found at the back of the eye; DR), diseases of the vitreous (clear gel-like eye fluid), the cornea (the clear layer at the front of the eye), conjunctiva (clear, the thin lining covering the front surface of the eye) and uvea (middle layer of the eye). Controlling high blood glucose is therefore important for these patients.

SGLT2is are oral medications used in the treatment of T2D to reduce high blood glucose. They function by reducing the reabsorption of glucose in the kidneys and elimination in the urine. Some SGLT2is treatment options are canagliflozin, dapagliflozin (Forxiga), empagliflozin, ipragliflozin (Suglat), tofogliflozin (Apleway), ertugliflozin, sotagliflozin (Zynquista) and bexagliflozin (Bexacat). However, knowledge of their effect on the occurrence of eye diseases compared to placebo or other blood glucose-lowering medications is limited and further analysis is needed.

This analysis included 47 studies. Patients had T2D with eye diseases and were assigned to receive either SGLT2is or a control. Control groups received either a placebo or other blood glucose-lowering medications such as metformin (Glucophage), sitagliptin (Januvia), glimepiride (Amaryl), gemigliptin (Gemiglo), semaglutide (Ozempic), glipizide (Glucotrol) and saxagliptin (Onglyza). Patients were followed up for 12 to 416 weeks.

The use of SGLT-2is was not associated with the occurrence of cataracts, glaucoma, retinal disease, and vitreous disease in patients. Overall, patients treated with SGLT2is had a 50% lower risk of developing retinal disease compared to the control groups. Compared to the controls, ertugliflozin reduced the risk of retinal disease by 53%, while the risk of DR was reduced by 56% with empagliflozin. The risk of vitreous disease was increased with the use of canagliflozin compared to placebo by 4.5 times.

The study showed that SGLT2is were generally not associated with the occurrence of eye diseases in patients with T2D. Ertugliflozin and empagliflozin may protect against retinal disease, while the use of canagliflozin may promote eye diseases.

The studies may have used different approaches for the diagnosis of eye diseases. Different medications were used for various periods. Data on eye diseases were based on reported side effects. Some studies had a small sample size.