HbA1c reduction following flash monitoring commencement is not independently associated with adverse diabetic eye disease outcomes in type 1 diabetes

Abstract

IntroductionIntensification of therapy has been associated with early worsening of retinopathy prior to subsequent risk reduction. We sought to assess whether glycated hemoglobin (HbA1c) reduction, following flash monitoring, was associated with early worsening.Research design and methodsAn observational study in 541 individuals with type 1 diabetes and paired HbA1c and eye assessment prior to and following flash monitoring commencement.ResultsChange in HbA1c was −4 mmol/mol (IQR −9–1) (−0.4% (−0.8–0.1)) and 25% achieved a fall in HbA1c of ≥10 mmol/mol. The occurrence of the composite end point (panretinal photocoagulation, macular laser or anti-VEGF therapy) was associated with baseline HbA1c >75 mmol/mol (9.0%) (HR 4.0 (95% CI 2.0 to 7.9), p<0.001) but not with fall in HbA1c of ≥10 mmol/mol (0.9%) (HR 1.6 (95% CI 0.8 to 3.2), p=0.203) over a follow-up period of 615 days (527–863). In multivariate analysis, diabetes duration (p=0.035) and prior retinopathy (p<0.001) were most predictive of the composite end point. Baseline HbA1c was the strongest predictor of worsening retinopathy (p=0.002) or new retinopathy (p=0.002) in multivariate analysis whereas change in HbA1c was not independently associated with either (p=0.930 and p=0.830, respectively).ConclusionsProgression of eye disease is associated with baseline HbA1c, diabetes duration and previous retinopathy and such individuals should be monitored during intensification of glycemic therapy. Reassuringly, the extent of glucose lowering does not appear to be an independent risk factor for early worsening of eye disease in this context.

Substantial HbA1c Reduction Following Intermittent-Scanning Continuous Glucose Monitoring Was Not Associated With Early Worsening of Retinopathy in Type 1 Diabetes

“…This assessment of individuals at high risk of microvascular complications (high HbA1c and long diabetes duration) accords with our earlier findings in an unselected group of individuals who commenced iscCGM within a single clinic in our center. 8…”

“…We have previously shown that in an unselected cohort of people with type 1 diabetes, comprising the first 589 iscCGM users in a single clinic, there was no independent association with extent of glucose lowering and EWDR (including the need for pan-retinal photocoagulation [PRP], macular laser or anti-vascular endothelial growth factor [VEGF] therapy). 8 However, it remains possible that those at high risk for microvascular complications may have a specific susceptibility to substantial reduction in HbA1c. To test this, we identified a cohort of individuals with high baseline HbA1c and long duration of diabetes and created two groups based on their initial HbA1c response to iscCGM: best responders, with a large decrease in HbA1c and non-responders, with no change or an increase in HbA1c.…”