Endocrinology

PCP submission

28yM with history of diabetic retinopathy, last a1c was in July 2022 and was 7.4 then. no recent labs but fingersticks were still high despite insulin and metformin. has prev taken ozempic at 0.5mg dose last summer, but stopped due to cost after couple mos. took bydureon but c/o regained wt so that was d/c. started on mounjaro a few months ago when AM fasting bg was running in 200s. was on 2.5mg dose x 4 wks in Jan and tolerated well and then increased to 5mg qweek in early Feb. Maybe about 2 months ago, after about 1 month of mounjaro or so, pt noticed his vision was worse like had difficulty reading road signs. Since this persisted x 2 mos, pt went to optometrist? and was told that his eyeglass prescription in both eyes worsened by “around a point”, more neg, like went from -2.5 to -3.5. Pt has referral to retinopathy clinic but waiting for appointment. His fingersticks are now at goal usually 100-110 AM and 110-120s in eve. I was concerned about possible worse diab retinopathy as blurry vision persistent x 2 months so switched pt to rybelsus 7mg qd for now (he just followed up w me in at virtual primary care video visit).

1. Could this be worse diab retinopathy due to mounjaro?
2. Stopped mounjaro and switched to rybelsus. When I looked ozempic and mounjaro up on lexicomp, both had a note about possible worse DR but supposedly per lexicomp rybelsus did not have that note. Is this correct?
3. Should I be doing something else like should I be switching out of GLP1RA altogether and use SGLT2 inhib instead, or is rybelsus ok from a diab retinopathy standpoint?

Specialist response

HI.Thanks for reaching out! Good questions. Sounds like you have a diabetic patient with alternating periods of poor then good control of his blood sugars who has been going through various changes in his medication over the last few months and during this period he has noted blurring of vision especially with road signs. Optometry has noted a change in his prescription possibly around 1.0 diopters more myopic.Patient has a history of diabetic retinopathy and is planned to revisit with a retina specialist. If this patient walked into my office with this history the first thing I would think of would be that the change in his blood sugar status is causing his vision to blur.This is a very common phenomenon whenever blood sugar levels change. The reason for this is that the blood sugar molecule gets absorbed into the patients ocular lens and creates swelling or enlargement during hyperglycemia and shrinkage when the blood sugar drops. Therefore if a patient is measured for glasses while his blood sugar is in the 200 range but then has his blood sugars dropped into the low 100s the glasses will no longer be correct.I usually mention this to patients ahead of time so they are not surprised when their blood sugars improve that all of a sudden their glasses are not correct anymore. Generally speaking I would expect improved BSs to lead to less myopia. The best time to get checked for glasses is when the blood sugar is in a reasonably good place for a few weeks and is expected to be reasonably stable going forward.In this case the optometrist is reporting more myopia but I don’t know what period of time he’s comparing that to and I’m getting the information third hand so I still believe change in blood sugar is the most likely explanation of his blur if its correctable by a change in glasses.However as you mentioned it’s possible that retinopathy could be getting worse and this is another explanation for blurred vision. Usually when this is the case the vision is not correctable even with glasses because it has degraded from macular edema that may accompany the retinopathy.The retina specialist will then need to do treatment such as laser or injections if this is the case. I don’t think I would make any further changes in the medication if you have the patient well controlled currently (as it seems to be now) until you hear back from the retina specialist clinic. When the blood sugar is not controlled then I would recommend further adjustments in medication with whatever medicine works best in this patient work further to get control of the blood sugar as the priority. If according to the retina clinic retinopathy is not causing macula edema then patient can get remeasured for glasses on his new regimen after BSs stable for several weeks. Symptoms that suggest a more urgent referral to in person evaluation by an eye specialist would include further worsening of vision, distorted or missing letters when he tries to read or any red tint or red floaters suddenly appearing in the vision. I hope this is helpful. Please reach out if you have more questions.