Glycated haemoglobin (HbA1c) variability may play an important role in guiding blood glucose control targets in diabetic patients and help predict the progression of adverse renal events or diabetic retinopathy (DR), a Chinese study found.  

Using online databases, researchers analysed 45 long-term studies, including 172,111 participants from multiple regions. Of these studies, 22 looked at the association between HbA1c variability and adverse renal events, eight looked at its association with DR and 15 included both outcomes.  

They found that in patients with type 1 diabetes, greater variation in HbA1c levels over time was linked to a higher risk of DR. One measure, coefficient of variation (how much HbA1c fluctuates relative to the average), was associated with a 15% higher risk. HbA1c standard deviation (how widely HbA1c values fluctuate) was also strongly linked to increased risk.  

In people with type 2 diabetes, both measures of HbA1c variability were also associated with a 12–19% higher risk of DR.  

Overall, the findings suggest that larger fluctuations in long-term blood sugar levels are associated with a greater risk of developing DR. “The core value of this study lies in the fact that HbA1c variability, as a modifiable risk factor, is expected to provide new quantitative indicators and a theoretical basis for optimising the management strategies of patients with diabetes mellitus,” they concluded.