Study identifies two risk factors for diabetic papillopathy in patients with type 1 diabetes

The phenomenon of early worsening in diabetic retinopathy during the first year with reduced glycemia has been well established in controlled clinical trials. But what about diabetic papillopathy? The pathogenesis is largely unknown, but case reports suggest that it too may follow rapidly improved metabolic control.  

To test this hypothesis, the authors set up this retrospective case-control survey including 2,066 type 1 diabetes patients followed for a mean of 4.85 years. Bilateral diabetic papillopathy developed in five patients, all of whom experienced a pronounced recent decrease in glycosylated hemoglobin A1C (HbA1c) levels, at a maximum rate of -2.5 (mean) percentage points per quarter year, which was significantly different from the changes in HbA1C observed in the remainder of the study population (P<0.001).Photographs recorded before the onset of bilateral diabetic papillopathy showed that all five patients had small cup-to-disc diameter ratios in both eyes (P<0.001).

An ancillary finding showed that three of the four patients who had diabetic retinopathy before diabetic papillopathy proceeded to develop high-risk proliferative diabetic retinopathy - a finding that further supports the theory that papillopathy and retinopathy progression both are early worsening phenomena.

The authors conclude, tentatively, that before a planned intensification of insulin treatment in type 1 diabetes, a fundus examination may help to identify patients with cup-to-disc diameter ratios of 0.18 or less. In these patients, extra care should be taken to avoid rates of change in HbA1c faster than -1.5 percentage points per quarter year to avoid diabetic papillopathy and, hypothetically, progression of diabetic retinopathy.